A sailor from HMAS Sydney literally crawled off a snow-covered and blizzard-swept Tasmanian mountain last month to save the lives of two bushwalkers.

Before AB Damien Cann attempted his lifesaving trek, he joined his mate LSCSO Brett Anderson to make sure the man and woman were warmed and protected.

The work by the two young sailors has subsequently brought praise from Tasmanian rescue police.

On the weekend of August 17-20 CMDR Daryl Bates and his ship's company in HMAS Sydney visited Hobart.

It was a period when icy winds drawn from the Antarctic swept not only Tasmania but Victoria and NSW.

Snow fell to the 400m level in Hobart with the 1270m Mount Wellington, behind the city, covered in a mantle of white.

Although the snow and ice closed the road to the summit, some sightseers set out on the 15km climb.

Among them were Damien and Brett, both of whom were well prepared.

While on the summit the two men took shelter in a hut from a particularly vicious blast of wind and snow.

According to Sydney's PRO, LCDR Ainsley Morthorpe, they were startled when a young couple staggered into the hut suffering the late stages of hypothermia.

"With the young man incoherent and the woman collapsing in front of them, Damien and Brett were forced to make some rapid and important decisions," LCDR Morthorpe said.

"As Brett utilised his own equipment and supplies to stabilise the couple, Damien prepared to battle the extreme weather to go for help.

Damien said later, "by this time our mobile phones had both frozen solid and if it had not been for my compass and map we would have been lost."

By now the visibility was down to three metres and Damien had to navigate by dead-reckoning to relocate the track back down the mountain.

"I got knocked over by the wind and snow.

"I had to crawl part of the way," he said.

Damien did find the track and walked for 35 minutes. He used another walker's mobile phone to raise the alarm. He continued down to provide a "sitrep" to responding paramedics.

A snow plough and a mountain rescue team made their way to the summit where Brett had kept the couple stable.

The couple was brought down and recovered in Royal Hobart Hospital.

As Brett said, "you can't take this sort of mountain for granted.

"You have to be properly prepared or you will die, even if the mountain is just one hour out of a big city."

Sergeant Paul Steane, the head of the Tasmanian Police Search and Rescue Squad, went with Damien and Brett back to the summit where he congratulated them on behalf of the Tasmanian Police, "you certainly impressed my squad ... well done."

By Graham Davis