Mr Lee is recovering in a Kathmandu hospital after his rescue on Wednesday, a day after he took to Twitter to complain of his worsening health.

According to his blog, Mr Lee was attempting to climb Mount Everest without oxygen tanks and was on his fourth attempt. On Facebook, he rejected a friend's suggestion that he abandon the attempt and use oxygen.

He attended Prospect High School in Launceston in the 1990s.

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After spending weeks at Chinese Base Camp, weather on Mount Everest finally cleared enough for him to make his attempt.

But on May 18, he started to report ill health.

Then three days later he told his followers he was having a "rough night" at Camp One, at an elevation of around 6000m, due to a "persistent chest infection".

He was found unconscious by Tibetan rescuers the next day.

The team of Tibetan alpine specialists used the yak to drag him to the safety of base camp.

Mr Lee, who now lives in Canberra, was reportedly taken to a hospital in Kathmandu where his condition has improved, The China Daily reported.

The team stumbled across Mr Lee at an altitude of 7500 metres on the northern slopes of the mountain on Wednesday last week.

Mr Lee's condition has improved from critical to stable.

His blog outlined his plans to climb 14 mountains above 8000 metres without oxygen or the use of drugs.

The current climbing season on Mount Everest has been particularly deadly, with 11 people dying so far in 2019 amid complaints of overcrowding, climber inexperience and not enough windows of opportunity to reach the summit.

Six months ago Mr Lee blogged about his experiences at the Blue Derby Mountain Bike Trails in Tasmania's North-East.

Australia's Department of Foreign Affairs and Trade has refused to provide any other details about his dramatic survival story, citing privacy reasons.

The heavy death toll from this year's climbing season has put the issue of overcrowding on the iconic mountain back in the spotlight.

Climbers have shared photos taken just below the summit, showing them queued up in a tight column, waiting for their moment to push for the summit.

Canadian adventurer and filmmaker Elia Saikaly says he's unlikely to ever return after the chaos he witnessed as he made the summit last Thursday.

Mr Saikaly returned from his eighth Everest expedition with a sense of abhorrence, saying he'd watched people clamber over dead bodies, only to die themselves.

"I cannot believe what I saw up there. Death. Carnage. Chaos. Lineups. Dead bodies on the route and in tents at camp four," he posted on social media after making it safely back to base camp.

"People who I tried to turn back who ended up dying. People being dragged down. Walking over bodies."

He later told the Ottawa Citizen he was unlikely to make another assault on the summit.

"It's a really messed up thing to be in a position where you have to walk over a dead body," he said by phone from Kathmandu.

"Do I think I'll go back? I don't think so. Not after this season. It was pretty horrific."

American doctor Ed Dohring, who made the summit a few days ago, told The New York Times it was "like a zoo" up there, with climbers jostling to take selfies and lined up chest to chest.

"It was scary," he said, describing how he'd had to step around the body of a woman who'd just died.

Nepal's tourism authority has responded to the cluster of deaths by saying overcrowding is not solely the problem.

The authority's director general Dandu Raj Ghimire said other factors were involved including only very brief windows of fine weather during which climbers could push for the summit.

Other veteran climbers have also pointed to the inexperience of some climbers and the pursuit of profits by climbing companies.

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