Canada is being forced to explain its polar bear policies to an international environmental watchdog.

The Commission on Environmental Co-operation, which is part of the North American Free Trade Agreement, has accepted a petition from a U.S.-based group that says Canada isn't following its own laws on protecting the bears.

In accepting the petition, the commission has found that the Center for Biological Diversity has registered a legitimate concern under the terms of the treaty.

"The commission found that we had a sufficient allegation and provided sufficient documentation of the violation that we can move forward in this process," Sarah Uhlemann, a lawyer with the center, said Friday.

The petition, filed in November 2011, alleges that Canadian officials ignored the most recent science on climate change and the loss of Arctic sea ice when they ruled last year against changing the status of the bear from "special concern" to  "threatened," which would rule out hunting.

It also says that the Tory government had already broken its own laws by being more than three years late in filing a mandatory management plan for the Arctic predators. The petition concludes by suggesting that hunting quotas for the bears set by Inuit co-management boards are unsustainable for some populations.

Uhlemann said Canada's most recent scientific assessment of bear populations minimized the impact of ice loss. The bears use sea ice as a hunting platform for seals, their primary food.

"They really didn't address the effect of climate change, which is the biggest threat to this Arctic species."

The U.S. listed polar bears as threatened in 2008, leaning heavily on a 2007 study that predicted the loss of sea ice could reduce bear numbers by two-thirds by 2050.

"The (Canadian) analysis dismissed this study as preliminary," Uhlemann said.

"It's not. In 2010, the same study was published in Nature magazine, which is one of the world's pre-eminent scientific journals."

Polar bear expert Andrew Derocher at the University of Alberta said Canada's assessment downplayed the impact of sea ice.

"Every polar bear scientist in Canada knew it was a flawed report from the outset," he said.

"They were told it was flawed and they chose to ignore the advice. The only position that Canada can really take now would be to do a new status assessment."

Adam Sweet, a spokesman for Environment Canada, said federal scientists conduct regular polar bear research and the government is currently developing a management plan for the animals, as required by legislation. Responsibility for management is shared by provinces, territories and regional wildlife management boards and a request for a new assessment would also have to involve those groups.

"We will be delivering a clear and timely response that illustrates how Canada has effectively enforced the Species at Risk Act with regards to the listing of polar bear," Sweet said in an email.