HAVRES-AUX-MAISONS, Que. - Freedom of speech will be at the centre of a courtroom battle that will pit the federal Fisheries Department against five people charged with violating the rules for those who head to the ice floes to observe Canada's controversial seal hunt.

Beginning Thursday, the five defendants -- all critics of the annual hunt off Canada's east coast -- will stand trial in a court on Isles de la Madeleine, the windswept archipelago in the middle of the Gulf of St. Lawrence.

They are charged with violating federal marine mammal regulations by coming within 10 metres of seal hunters. The offence is alleged to have occurred during the 2006 hunt in the southern Gulf, near the Cape Breton coast.

All five have pleaded not guilty.

"We will vigorously defend ourselves against these charges," said animal rights activist Rebecca Aldworth, director of Canadian wildlife issues with the Humane Society of the United States.

Clayton Ruby, counsel for the five and one of Canada's best-known defence lawyers, said Wednesday he will present video evidence that he says will prove his clients are innocent.

He said federal prosecutors have already dropped an earlier charge of obstructing the hunt. The remaining charge carries a maximum fine of $100,000.

"It really is about whether the government can continue to keep people from getting photographic images and putting them around the world so that the whole world knows what we do," Ruby said in an interview.

Federal Fisheries spokesman Phil Jenkins said the department continues to hands out observer permits every year for the hunt, and he stressed that recent amendments to Marine Mammal Regulations were not an attempt to deny access.

"They are just a clarification," he said. "There isn't anything new in there that would lead to any kind of restriction on observation."

The case, to be heard before a Court of Quebec judge, is expected to last two days.

The defendants are representatives of Humane Society International and Humane Society of the United States.

In March 2006, the five had been involved in filming the annual commercial hunt in the Gulf, hoping to capture images of animal cruelty for their anti-sealing campaign.

During the course of their work, which was carried out on a small, inflatable boat, RCMP and federal Fisheries officers charged them with violating the 10-metre buffer around sealing vessels and sealers.

The defendants in the Quebec case are Canadians Rebecca Aldworth and Andrew Plumbly; Americans Chad Sisneros and Pierre Grzybowski, and British citizen Mark Glover.

In a news release, Humane Society International said the charges "are part of an effort by the Canadian government to close the curtain on this gruesome enterprise."

Ruby said federal prosecutors in the case, who did not return phone calls on Wednesday, plan to call three witnesses -- an RCMP officer and two Fisheries officers -- who will testify the defendants were within 10 metres of sealing activities.

"We're going to call our accused and some experts who performed very sophisticated tests on videos who will say that is absolutely not the case," he said.

The 2006 seal hunt was one of the most turbulent in decades.

Clashes between sealers and animal rights activists in the Gulf of St. Lawrence and off Newfoundland and Labrador highlighted growing tensions between the people who want to stop the slaughter of young seals and those who rely on it as a much-needed source of income.

High-profile appeals by celebrities, including a widely covered visit to the Gulf by superstar Paul McCartney and the re-emergence of French actress Brigitte Bardot, signalled a massive new effort by animal rights groups to stop the hunt.

On the ice floes, the presence of protesters was beyond toleration for some sealers who resorted to flinging seal guts at observers and, in several cases, attempted to ram the small, inflatable vessels used by protesters and journalists.