Gay people in Canada may have the right to marry taken away just a year after the nation granted it.

A new Conservative government, that campaigned on the promise that it would allow Parliament to vote on whether to reopen the issue, takes power next week .

If Parliament approves the motion, the government, led by Stephen Harper, would then change the definition of marriage back to that of a union between a man and a woman. The gay marriage law was brought in by the outgoing Liberals.

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

“There’s a real risk that this motion could succeed … and we need to deal with it,” said Laurie Arron of the gay rights group Egale told Reuters.

“We don’t want to take any chances. We’ve got social peace right now. We’ve got the right to marry and it’s working and nobody’s been hurt as a result.”

Canada’s social conservatives have previously voiced displeasure that the House of Commons voted last June by 158 to 133 to allow same-sex marriages.

Reuters revealed that Mr Harper is committed to same sex rights and promises to ensure the 3,000 gay marriages that have already taken place would not be annulled. Some observers speculate that he secretly wants to lose the vote and thereby ensure the issue does not dominate headlines, thereby alienating centrist or soft-left voters whose support he will need at the next election to win a majority.

Mr Harper is under pressure from groups such as Focus on the Family in Canada to produce results. “If he fails to deliver on this issue, he’ll have to deliver on some significant other issue,” Derek Rogusky told Reuters. One example would be raising the age of consent to 16 from 14.

Mr Rogusky suggested social conservatives might not support Harper next time if there was no movement on issues important to the movement, prompting the senior Conservative to reply: “They are going to support us. They’re certainly not going to go vote for the Liberals.”

The Liberal government introduced its same sex law after courts in some of Canada’s most powerful provinces ruled in favour of gay marriages.

Groups such as Egale say banning same sex marriages would be unconstitutional and would eventually be struck down by the Supreme Court. The Conservatives say the courts should respect the wishes of legislators.

Canada last year became only the fourth nation in the world to allow same sex marriages.