Animal Alliance of Canada and Zoocheck have initiated a court action through a Toronto law firm, in an effort to head off the spring bear hunt in northern Ontario before it begins May 1.
They want a judicial review of the government's decision to open the hunt.
Julie Woodyer of Zoocheck said the hunt is unconstitutional because it violates federal animal cruelty laws.
In an interview Thursday with CBC News, she said "it is a known fact that, when bears are killed in the spring, it includes lactating females, so the cubs are orphaned and there's no ability to find those animals so they starve to death."
Zoocheck and the Animal Alliance of Canada also argue the hunt goes against sections of the Environmental Bill of Rights and the Environmental Assessment Act. The matter will go before a judge on April 29.
'It is not responsible for a provincial government to ignore the concerns of thousands of residents who are concerned about their public safety.' - Ontario Natural Resources minister David Orazietti
The hunt, which the government calls a pilot project, is set to run for six weeks in eight wildlife areas known for having the most incidents involving bears. Those areas include around Thunder Bay, Sudbury, Sault Ste. Marie and Timmins.
Ontario Natural Resources minister David Orazietti said school children in some areas of northern Ontario can't go out for recess because of threats from bears.
"It is not responsible for a provincial government to ignore the concerns of thousands of residents who are concerned about their public safety," he told reporters Thursday in Toronto.
Orazietti said the government received nearly 50 resolutions from mayors and city councils across the north asking for their communities to be included in the approved hunting areas.
The Ontario Federation of Anglers and Hunters issued a statement saying it doesn't want "big-city animal rights extremists" to derail the hunt.