More than 20cm of ice was packed on to the alpine luge track a fortnight ago, of which little more than 7cm remains.
Naseby luge coach Greg Jones, of Canada, said he and others had been fighting hard to keep what was left of the frozen track, particularly ahead of a scheduled demonstration for the Winter Games New Zealand at the end of this week.
"The Winter Games is going to be the end of our season," he said.
Mr Jones said the luge could be used with about 3cm of ice on it, although gravel was starting to show along the edges that touch the luge's wooden sides.
As the sun beat down on the track yesterday afternoon, Mr Jones swept surface water off the ice to maintain what was left.
"We've been fighting pretty hard to keep it until now. It's going to cost too much to keep it open any longer than this week."
Tarpaulins had been used to cover the ice, plus refrigeration pipes underneath to help keep it as frozen as possible.
Fewer people had been allowed on to the track in the past two weeks, as another measure to preserve the thinning ice cover.
Mr Jones said there was just enough ice on the track and snow in a storage pit to make the luge last for the Winter Games demonstration.
"We still have a little bit of snow stashed away which we will be able to use to fill the holes.
Even if we have part of the track closed off and only use the top part we will be all right," he said.
Mr Jones said it was too warm to make any more snow.
"The last time we made snow was in June. It [the luge] is actually holding up pretty well considering."
The luge officially opened on June 29.
