Peak Learning’s Chief Guide

Zac Zaharias, CSM

Zac is the founder of Peak Learning Adventures and head guide. He has been climbing, walking and skiing for over 40 years. His great passion is mountaineering, with 23 expeditions to the Himalaya and Karakoram ranges covering Nepal, Tibet, Pakistan and India along with 11 seasons in New Zealand. Zac is one of Australia’s most experienced high altitude mountaineers with ascents of 6 of the 14 world’s highest mountains above 8000 metres in elevation. He has been on three Expeditions to Mt Everest and reached its summit in 2010. Zac was the last person to carry an SLR film camera to the summit!

Zac has outstanding outdoor leadership credentials. He has run adventurous training programs in the Army, led many Himalayan expeditions, worked as an outdoor guide for a number of companies and consults for the Outdoor Recreation industry. He has also led numerous treks and climbs in Bhutan, Nepal, Africa, New Zealand, Tibet, India and Pakistan. Zac is also a Level 4 cross-county ski instructor and regular competitor at the World Masters Cross Country Ski Championships.

Zac was a career soldier for 31 years and is currently serving as a Lieutenant Colonel in the Army Reserves, having recently commanded an Engineer Regiment of 350 soldiers. Along with his love of military history Zac brings his wealth of military experience to the PNG battlefield treks and tours, which he has been guiding for 17 years.

Senior guide

Matt Rogerson

As a career Army Officer and outdoor professional, Matt has a wide skillset and experience in planning, hands on leadership and risk management of complex activities in remote and wilderness locations.

An enthusiastic mountaineer, Matt has participated in and led several significant mountaineering expeditions, including making the first Australian ascent of Dhaulagiri and the third ascent of the remote sub-Antarctic Mawson’s Peak on Heard Island. Matt has led three geologic survey expeditions to remote Greenland fjords.

He has worked extensively in a wide variety of outdoor guiding roles, including Himalayan trekking and mountaineering, battlefield study tours in PNG, corporate experiential learning events, academic field surveys and work with veterans affected by their service. For Army he designed and led a noteworthy alpine resilience exercise for veterans suffering PTSD.

Senior guide

Andrew Lock, OAM

High altitude mountaineer and global adventurer, Andrew is the only person in the British Commonwealth to have climbed all 14 of the world’s 8000 metre ‘death zone’ mountains, a project that took 23 expeditions over 16 years.

He made the first Australian ascents of 6 of those peaks and summited Mt Everest twice. He has worked as leader and guide for climbing, trekking and adventure groups around the world since 1990, as well as for the Australian National Antarctic Research Expeditions, and has trekked, climbed, paddled, sailed, skied and adventured on every continent on earth. Andrew is Ambassador for Scouts Australia, the Sir David Martin Foundation and the Australian Himalayan Foundation. He is the author of SUMMIT 8000 and featured in the Discovery documentary series Ultimate Survival: Everest.

Senior Guide

Chris Warner

Chris is an accomplished climber with over 20 years experience of expeditions. He has climbed on five 8000ers including Everest and K2 as well as many other peaks in the Himalayas.

He has also completed many first ascents on difficult peaks in remote regions of the world such as Baffin Island, Chukotka in Russia and Kyrgyzstan. He climbs extensively in the European Alps where he now spends most of his time climbing, skiing and paragliding. After selling his rope access company in Australia he now enjoys taking small groups on adventures into the mountains and sharing the explorations of new places.


Peter Lambert

Peter Lambert began climbing in the Southern Alps of New Zealand, quickly progressing to trekking and climbing in more remote destinations. He has climbed the highest mountains in the USA, western Europe and the Himalayas. Significant ascents include Denali, Alaska (6190m); the second ascent of the south-east face of Nilgiri North, Nepal (7061m); the first Australian ascent of Broad Peak, Pakistan (8046m); and as a member of the successful Australian Bicentennial Everest Expedition (8850m) he climbed to within 300 vertical metres of the summit. His second 8000er was the ascent of Shishapangma Central (8027m), in 1999.  In 2001 he was a member of the Australian Everest 2001 Expedition in Tibet, reaching 7,000m on the North Col. He has trekked extensively in Nepal including Everest Base Camp, Three Passes trek, Annapurna Circuit and Annapurna Sanctuary, Langtang and Gosainkund Lakes. When he isn’t trekking, he works as cross-country ski instructor in Perisher.

Expedition doctor

Dr Annemarie Newth

Annemarie is an experienced medical practitioner specialising in Emergency Medicine and Hyperbaric Medicine with extensive experience in critical care. Born in San Francisco to New Zealand parents she has been diving since the age of 15 and worked as a dive master since the age of 18. She also spent six years as a medic in the New Zealand Army Reserves.

She recently joined Peak Learning as a guide and expedition doctor and has led treks to Kokoda and Mt Kilimanjaro. Her wealth of experience working in remote areas makes her an asset on e very expedition. Her nickname is “ Am” and is a great raconteur when the going gets tough. When she isn ’t diving, treating patients or guiding, Annemarie is an avid hiker and triathlete, having competed in Australia and NZ.


Mark Walton

Markham St Clair Walton, aka “JB” born in NSW spent the 60s to early 70s in an 1805 homestead in the then quite rural south west Sydney town of Campbelltown. A journey into the Royal Military College, Duntroon commenced in 1974, (and gave him the “JB” nickname from the ghastly TV show “the Waltons”), graduating to the Royal Australian Artillery. His connection with Defence continues to this day with over 40 years distinguished service in the Army, currently with the rank of Major. JB is a specialist PNG Guide and is renowned for his energy and humour with clients and the local PNG staff.

JB also gained a passion for surfboats and still competes currently rowing with the North Bondi club. He recently returned from a 100km surfboat race around the Dardenelles in support of events surrounding the 100th anniversary of ANZAC. As well as a keen interest in all things adventurous particularly those involving ropes and rock, and tracks and packs!

Living in the Blue Mountains makes sense for the adventure parts of JB’s life while boats and forays to the coastal beaches provide a short holiday-like break from mountain life.

PNG historian

Nikki George

Nikki has 32 years experience in the tourism industry, 20 years as a dive instructor and 14 years as a trek leader in PNG. She has completed 69 Kokoda treks in 13 years, 11 Black Cat, Mt Wilhelm, Mt Albert Edward and Shaggy Ridge. Additionally, she has led treks to Sandakan in Borneo, the historic death march of Australian and British POWs during WWII.

As a trek guide Nikki has been privileged to experience and engage with different cultures in magnificent natural environments. Nikki has witnessed children growing up along the tracks, befriended and established strong working relationships with the communities.

When you trek with Nikki you are with a veteran guide of the Kokoda Track, someone who has thoroughly researched this extraordinary campaign and you will discover things that you won’t read in books.. You are also with someone who is passionate about the people and cultures you’ll meet as you take part in this life changing, mental, emotional and spiritual journey.

Nikki has built the most wonderful friendships with the local villagers Over the years she has talked to local elders who were there during WWII, war historians and senior military personnel who have walked the track with her.

In Nikki’s words, “what inspires me about the historic Kokoda track, is the human sacrifice and the endurance of the men that fought, fell or survived for their country. For me, I feel passionately about bringing all these experiences to fellow trekkers”.

PNG historian

Reg Yates

Reg Yates brings a wealth of experience trekking in PNG since 1984 as well as outstanding knowledge of military history.

He first walked with small groups of ADF soldiers from 1984 to 1989 on ‘adventurous training’ exercises including: the Kokoda Trail; the Bulldog-Wau Road; the Wau-Salamaua WW II tracks; walked from Kompiam, WHP to Eram on the Yuat River and boated to Tambanum village; crossed the Saruwaged Range of Peter Ryan’s “Fear Drive My Feet”; and rafted down the Watut River.

Reg worked for 36 years as a Qualified Ambulance Paramedic (QAP) with Ambulance Service Victoria, Melbourne, retiring in 2009. Reg enlisted in the CMF in 1971 and was an Army Reserve Infantry Captain for 20 years from 1980 to 2001.

Reg continued visiting PNG on ADF ‘study tours’ during 1990 – 1998, travelling ‘solo’ but always accompanied by local guides or carriers: Shaggy Ridge; the Hindenburg Wall section of Karius and Champion’s 1928 crossing of the headwaters of the Fly and Sepik Rivers; Finschafen, Scarlet Beach and Sattelburg; paddled a dugout canoe on the Sepik River from Frieda River junction to Ambunti; boated through the Gulf of Papua delta from Hohola to Kikori; and at various times visited Daru Island in Torres Strait, Mendi and Tari, Mt Bosavi, Lake Kutubu, Mt Wilhelm, Kiunga, Lake Murray, Wewak and Mission Hill, Rabaul and Tol Plantation, Kavieng, Manus and Baluan Islands, and Milne Bay.

Reg has walked the Kokoda Trail 51 times; Shaggy Ridge 8 times; Wau-Salamaua 6 times; the Bulldog-Wau Army Road 3 times; Rabaul-Tol Plantation 5 times.


Dr. James Strohfeldt

James has been climbing rock, ice, big wall, Alpine and Himalayan peaks for four decades. His ascents include El Capitan in Yosemite, Denali’s Cassin Ridge in Alaska, and Mt Everest. He considers the mountains his true home, an inexhaustable source of physical, mental and spiritual health.

He has made many solo journeys: Mt Aspiring in NZ, the Matterhorn, a North to South traverse on foot and by raft of the Brookes Range in the Arctic Circle, long winter ski tours in the back country of Colorado and the European Alps. In Australia, he’ll head into the bush at every opportunity, preferring inclement weather that empties the ranges and stirs the senses. He has also guided trekking peaks in Nepal and taught rock climbing to school children in the Grampians, relishing the opportunity to share his home turf and teach the skills necessary to travel safely in the mountains.

A medical practitioner, James has extensive experience on many expeditions treating general medical, altitude-related and cold injuries. He works as an Assistant Surgeon in orthopaedics and neurosurgery in Melbourne. If pressed, he may tell you about the time he amputated a Sherpa’s leg in the Khumbu, and the subsequent canine intervention! He has also worked for 25 years as a psychoanalyst in private practice.

Expedition doctor

Dr. Renee Farrar

Renée is a mountaineer and an emergency medicine doctor. She gained her BMBS in the UK and has achieved her UIAA Diploma of Mountain Medicine. Renée has practiced as an expedition doctor in a number of countries and climates worldwide, but especially loves the mountains and snow. Has been climbing since she was a teenager and now mainly climbs in Europe and the Southern Alps, Iceland and Norway.

When she’s not mountaineering, she’s road cycling or writing as a freelance journalist. She’s written for medical journals and some extreme sport press. Known for her brightly coloured climbing gear and chirpy nature!

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