Zac Zaharias has scaled Mount Everest three times and made it to the summit once, but says overcrowding on the world's tallest peak has been getting worse in recent years.
The experienced Canberra climber says an oversaturation of travel companies offering trips for tourists up Everest has led to more dangerous conditions.
The comments come as Canberran Gilian Lee was rescued after being stranded unconscious on the mountain at an altitude of 7500 metres.
This year's climbing season has been one of Everest's deadliest, with 11 people losing their lives.
"A lot of companies are out there of dubious quality, and a lot of tourists don't know what they're doing," Mr Zaharias said.
"Most tourists see a sherpa and they think they know what they're doing.
"I've seen what happens when people go with operators who don't know what they're doing because lives are put at risk."
The climber was part of an Australian Army expedition on Mount Everest in 2001 which turned deadly, after three Australians accompanying the expedition died in an avalanche.
During the expedition, a South Australian climber from another expedition died in his arms after succumbing to exhaustion while trying to reach the summit.
Mr Zaharias said while the Canberra climbing community is a tight-knit one, many had not heard of Gilian Lee.
Mr Lee was attempting climb Mount Everest without the use of oxygen tanks and had sustained a chest infection at about 6000 metres.
On social media, Mr Lee's brother Ian said his condition had improved after the climber was taken to a Kathmandu hospital, and was expected to be out of intensive care in coming days.
Mr Zaharias set up his own adventure travel company, Peak Learning Adventures, 15 years ago, and said while he organisations expeditions to other parts of the Himalayas, he avoids Mount Everest.
"I've been there many times before but I don't go there now because of overcrowding," he said.
"In Nepal, there's no standards in terms of quality or experience in order to be a guide."
The climber said queues of people on the mountain waiting to reach the summit had been some of the worst he had seen.
"There were photos of long lines a few years ago lower down the mountain, but this has been the worst it's been so high near the summit, and that's exacerbated the fatality numbers," Mr Zaharias said.
Canberran Laura Darlington reached the top of Everest alongside her husband Ben in 2016.
She said there was crowding near the summit during her ascent due to there being a limited number of days where the weather conditions were advantageous.
"There's a big jetstream of wind that sits on top of Everest and you need that to lift off so it's calmer for climbers, otherwise there's winds of more than 100km/h at the top," Ms Darlington said.
"Above 8000 metres they call it the death zone because the oxygen levels are one-third of what they are at sea level, so you're struggling to take in oxygen.
"Even if you're using supplementary oxygen, your body is slowly dying."
Ms Darlington said while part of the challenge is reaching the top of Mount Everest, the most dangerous challenge is the descent.
"Most of the deaths occur on the way down, and the longer you spend above 8000 metres, it eats into your ability to descend," she said.