US members of a breakaway Mormon polygamous sect protest alleged persecution [GALLO/GETTY]

The supreme court in British Columbia has begun hearings on whether Canada's anti-polygamy law violates rights to freedom of religion guaranteed by the constitution.

The court is focusing on a breakaway sect of the Mormon church that has practiced multiple marriages at its compound in rural British Columbia since the late 1940s.

"We are beginning on an historic reference," Robert Bauman, the chief justice of the court said on Monday.

This could also expand in scope  to include members of polygamous Muslim communities.

Condoning abuse

Canadian prosecutors have previously declined to pursue polygamy cases. Critics of the practice said the government was condoning abuse of women and children.

Craig Jones, a lawyer for the province, has warned a judge that declaring polygamy a protected religious practice would make Canada the only Western country to allow multiple marriages.

Canada's westernmost province took the rare step of asking the court to rule on the law last year, after a judge threw out polygamy charges against two church sect leaders.

At the time, a provincial spokesman said polygamy causes "serious social harms," and Rob Nicholson , a federal justice minister, has said it "has no place in modern Canadian society."

'Religious right'

Winston Blackmore and James Oler, sect leaders, have argued they have a religious right to practice polygamy under Canada's constitution.

That claim has so far stalled government attempts to prosecute them, despite police investigations going back 20 years.

Each man heads rival factions of the Church of  Jesus Christ of Latter Day Saints near Bountiful, in the province's  remote southeast corner.

The church is a breakaway polygamous sect of the Church of Jesus Christ of Latter Day Saints, based in the United States, where some  members have been successfully prosecuted on charges related to  polygamy.

A final ruling is likely to take years and the case is expected  to eventually be taken up by the British Columbia court of appeals and perhaps Canada's federal supreme court.

Source: Agencies