An Australian soldier's rescue from Mt Aspiring is thought to have cost New Zealand taxpayers at least $150,000 and 500 volunteer hours.

Terry Harch was hospitalised last week with mild frostbite after spending three days trapped alone on mountain in the South Island national park, and then another night with rescuers.

It is not the first time Harch has been saved from a mountain in the Southern Alps. In 2013, he and a friend were rescued from New Zealand's second highest mountain, Mt Tasman.

SUPPLIED Terry Harch sheltering in a narrow crevasse awaiting rescue from Mt Tasman in 2013.

In both cases daring helicopter rescues were required to save him after he became trapped on a mountainside in deteriorating weather.

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He is also known to have successfully reached the summit of Mt Cook in 2011 and 2014.

WANAKA SEARCH AND RESCUE Rescuers at the site where Harch was kept safe while awaiting rescue on Mt Aspiring.

Confirmed costs for last week's rescue are not yet available but it is understood the two Squirrel helicopters used by Aspiring Helicopters were charged out at about $3000 an hour. The larger helicopter, owned by Southern Lakes Helicopters, cost about $5000 an hour.

The operational hours, which included searching for Harch after his tracking device was activated and waiting for weather to clear to remove him and rescuers from the mountain, have not yet been calculated.

One source estimated it would have been at least 50 hours. The Rescue Co-ordination Centre, which is part of the Ministry of Transport, will be responsible for covering the bill.

Harch went missing in the South Island's Southern Alps mountain range.

Wanaka search and rescue spokesman Phil Melchior said his team, including the four rescuers who stayed on the mountain with Harch, put in about 500 volunteer man hours in total.

"Virtually all of these people are self-employed. Most of these guys gave up three or four days' pay to do this."

Some of the team returned on Monday to collect more gear left on Mt Aspiring.

SUPPLIED Harch has been rescued from Mt Aspiring and Mt Tasman.

"One's a builder and one's a painter. They asked if we could organise someone to sort the stuff out when we get back because they needed to get back to work."

The rescuers did not seek any compensation "because they believe in what they do" but there was a significant cost to them, Melchior said.

In the 2013 case, Harch and a friend known only as Gareth reached the summit of Mt Tasman, but when they decided to take a different and unfamiliar route down the mountain their day trip turned into a three-day ordeal.

SUPPLIED Harch pictured at the start of an ill-fated ascent of Mt Tasman in 2013.

With night approaching they realised they were off course and could see only about five metres in front of them, Gareth said in an interview with Stuff.

"We'd been leading from one blind alley into another, trying to negotiate a route down through a crevasse and serac maze. We'd find drops of several hundred metres when we thought we were getting somewhere, and big overhanging ice cliffs, and all manner of unspeakable horribleness."

The forecast had predicted bad weather would settle over the area for about two days and they dug into a narrow crevasse to await rescue, which came 38 hours later.

SUPPLIED/DOC Climber Gareth (surname unknown) waves to an approaching rescue helicopter from thousands of metres up Mt Tasman. He and climbing partner Terry Harch sheltered in a narrow crevasse for about 38 hours after becoming trapped in bad weather on the mountain.

They were reported overdue and a flashing light was later spotted on the mountain at their location.

A search and rescue crew flew in a helicopter to the site where they were found the men suffering from fatigue and the early stages of frostbite.

"They were in the middle of a face surrounded by ice cliffs and crevasses and ice falls that were falling down and avalanching," team leader Karen Jackson said at the time.

WANAKA SEARCH AND RESCUE The spot to the left is Harch as he could be seen in the snow on Mt Aspiring from a rescue helicopter.

Melchior said he did not know how Harch got into difficulty on Mt Aspiring last week but "he did an extremely good job of keeping himself alive".

It is unknown if Harch is still in the hospital as he, his family and Australian Defence Force representatives have refused all interviews.