Stranded tourists spend icy night on Mt Cook

Two foreign tourists, one thought to be suffering from hypothermia, were to spend last night on NZ's highest mountain in temperatures of minus 20C after weather hampered search efforts.

The Rescue Co-ordination Centre in Wellington received an alert from a locator beacon on Mt Cook's Middle Peak at 3.15pm yesterday.

The beacon was registered to a Southland company which had hired it to two male tourists in their 20s from Europe. They had left contact details of a friend with the company and with the Department of Conservation.

After receiving the alert, the rescue centre contacted the friend and discovered one of the men had called him on a cellphone saying his companion was suffering from hypothermia and they feared they would be unable to get down the mountain.

Search and rescue personnel made contact with the pair by cellphone and it was understood the man had recovered somewhat after finding shelter and wrapping himself in a sleeping bag.

Mission co-ordinator Geoff Lunt said the Lakes District Air Rescue Trust was asked to send a rescue helicopter to find the climbers, but poor visibility because of low clouds meant it was unable to fly.

The weather was not expected to clear until this morning.

"They have built themselves a bivouac and they have sleeping bags and other equipment which will help them sit out the night."