Project director and ice team leader Pen Hadow and his colleagues Martin Hartley and Ann Daniels are now down to half rations and fighting to survive in brutal sub-zero weather conditions.

"We're hungry, the cold is relentless, our sleeping bags are full of ice and, because we're not moving, the colder we get," Hadow said Tuesday in a statement from the London headquarters of the Catlin Arctic Survey.

"Waiting is almost the worst part of an expedition as we're in the lap of the weather gods. This is basic survival."

The expedition set off on a 85-day hike on February 28 when the three were dropped off by plane on an ice floe some 668 miles, (1,075 kilometers) from northern Canada.

During the past 17 days temperatures have consistently dropped below minus 40 degrees Celsius (-40 degrees Fahrenheit), and have been accompanied by strong winds increasing the chill factor.

Bad weather has forced three attempts to drop food supplies to the team on a landing strip close to their camp to turn back.

The support team is now studying satellite images hoping to see the weather improving before another supply plane can risk taking off from Resolute, a small Inuit hamlet on Cornwallis Island in Nunavut, Canada.

But once the team has been re-supplied a new challenge awaits them, as satellite images show a huge stretch of floating sea ice in their path has broken up leaving an Arctic river in its place.

The break in the ice stretches for tens of kilometers, barring the team's progress northwards, meaning they will probably have to swim across to reach their destination.

Head of operations, Chip Cunliffe, said in the statement that the extra supplies, including batteries and cooking fuel, were urgently needed.

"Re-supplies can be difficult if the weather turns against us, but we now have an urgent need to reach them," he said.

He added that once the team is ready to go on the London headquarters will continue to search for "an ice bridge that could get them across the rift without going into the water, even if it means a substantial alteration in their route."

Hartley, the team's photographer, who has frostbite in his left toe, said he had hoped the supply plane would arrive Tuesday in time to celebrate his 41st birthday.

"We've just heard we're not going to get a re-supply today. I had hoped we might celebrate my birthday with fresh supplies, but right now there's no prospect of a party," he told survey's headquarters in London.

The team aims to gather data to complement satellite and submarine observations to measure the sea ice and plot how fast it is disappearing.

Global warming is believed to be the main culprit in the rapidly melting north polar ice cap that is freeing up new sea routes and untapped mineral resources on the ocean bottom.

All rights reserved. � 2005 Agence France-Presse. Sections of the information displayed on this page (dispatches, photographs, logos) are protected by intellectual property rights owned by Agence France-Presse. As a consequence, you may not copy, reproduce, modify, transmit, publish, display or in any way commercially exploit any of the content of this section without the prior written consent of Agence France-Presse.