Delayed ice formation along the west coast of Canada's Hudson Bay has put hundreds of polar bears at risk of starvation, wildlife experts say.

The Canadian Ice service, a division of Environment Canada, says warmer-than-usual temperatures have put ice formation four weeks behind schedule, Canadian Broadcasting Corp. News reported Thursday.

Sea ice is critical for polar bears, which use it as a platform from which to catch seals and other marine mammals.

While some 300 bears in the area appeared to be in good condition in a recent aerial survey, conservationists worry the animals' good health could deteriorate quickly if sea ice does not begin to form in the next few weeks.

"The longer that ice is in forming, the longer the polar bears have to survive on the fat reserves they put down in the spring and conserved right through the summer," Peter Ewin, an Arctic specialist for the World Wildlife Fund, says.

"The later it gets, the more weak bears there are who probably aren't going to make it through," he said.