WINNIPEG - One of Manitoba's top aboriginal leaders says climate change is threatening crucial ice roads, driving up prices in northern native communities and underlining the need for the federal government to build more permanent highways.

Grand Chief David Harper, who represents the province's northern First Nations, says unseasonably warm weather this winter has meant ice roads aren't even close to being constructed. That means another year in which supplies such as groceries, fuel and construction materials are scarce and expensive in remote communities.

Aboriginal elders have predicted a warmer winter this year with a late cold snap that is likely to come too late to be of much use, Harper said Tuesday.

"We've got to prepare for the worst. It's going to be a small window of opportunity."

The chance to build and use ice roads -- which help connect about two dozen fly-in aboriginal communities to the south -- has been shrinking. Aboriginals and environmentalists say Manitoba's winter season is growing shorter. Ice roads across frozen ground, lakes and rivers that have typically been open for 60 days are now sometimes only usable for about 20.

The winter transportation system is vital. The province estimates some 2,500 shipments of staple items are transported each year by trucks over 2,200 kilometres of icy road instead of being flown in at great expense.

In 2010, some aboriginal chiefs declared a state of emergency as warm weather turned their winter roads into mucky quagmires, stranding some truckers and causing fuel shortages.

It's clear dozens of northern communities can't rely on ice roads any more and the federal government must help construct more permanent routes, Harper said. He and other aboriginal leaders intend to raise the issue with Prime Minister Stephen Harper at a First Nations summit later this month.

"All-weather roads into the northern region have to be taken quite seriously from now on," Harper said. "Saskatchewan did it. Quebec did it. We've got to speed up the process."

Aboriginal communities have been raising the alarm about melting winter roads for several years.

A 2006 study by the Centre for Indigenous Environmental Resources found the shortened winter has a snowball effect. The study said weak ice on lakes makes it harder to trap and fish, while healthy groceries are in shorter supply when fewer trucks make it up from the south. That can lead to an increase in chronic health problems such as diabetes.

The shortened winter hauling season also exacerbates housing shortages in northern communities since many construction materials can only be transported overland, the study said.

Provincial officials are more optimistic about the coming winter.

Larry Halayko, director of contract services for Manitoba Infrastructure, said crews are already packing down snow so frost can penetrate the ground, although he admits warm weather has put them about two weeks behind schedule.

If the province gets more seasonable temperatures, some roads may open by the end of the month, Halayko said. They may be subject to load restrictions, though, and may close early depending on the weather.

"There are always concerns if we have warmer weather," he said. "But we've had warmer falls in the past and ended up having a very good season in the end."

The province has done what it can to mitigate the effects of warmer temperatures, he added. Some 600 kilometres of the road system have been moved off ice and onto land.

But, in the end, the road system needs sub-zero temperatures to work.

"You need Mother Nature, that's for sure," Halayko said.