Protest groups have today begun their campaigns on the issue of gay marriage.

Canadian Prime Minister Stephen Harper announced a free vote on the law last week scheduled for this Autumn.

Anti gay marriage group Man and Woman Union gathered today to raise awareness of the vote, Warren Booth, organiser of the organisation, told the CanWest news agency, “I know MPs make their break soon for a couple of months, but we want to leave them with a thought before they take off for their vacation.”

“While we’re up there, if there are MPs who don’t know which way to vote, hopefully by seeing us and our passion against this, maybe we can help sway their opinion and they’ll vote against this.

“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.