Canada will revisit its laws on same sex marriage next week.

A debate on same sex marriage will start on Monday in the country’s Parliament after a manifesto pledge from Conservative Prime Minister Stephen Harper that a debate on banning gay marriage in Canada would be held.

Mr Harper announced in his manifesto that there would be a free vote on the issue.

Anti gay marriage group Man and Woman Union have been gathering since his announcement to raise awareness of the vote, Warren Booth, organiser of the organisation, told the CanWest news agency, “”If God says don’t do it, you don’t do it. For us it’s a no-brainer. It’s not a grey area, it’s black and white, what they’re doing is sinful in the eyes of the Lord. Don’t get mad at us, we’re the messengers.”

Gay group Equal Marriage’s Laurie Arron said: “There is no doubt that equal marriage will continue, but it’s very difficult to have this debate continue, to hear things said about lesbian, gay, bisexual and transsexual people and to have the public be questioning our status as full citizens.

“I think the MPs who are undecided are all personally against reopening everyone I’ve spoken to,” Ms Arron said, adding that it is “unclear” whether they will “vote with their conscience or succumb to the pressure.”

The change in the law would constitutionally define marriage as a union between a man and a woman. The gay marriage law was brought in by the outgoing Liberals.

Both supporters and opponents say any vote would be very tight, especially since he does not control a majority of the 308 seats in the House of Commons.

Marriage was opened up to same sex couples in Canada last year.