Prime Minister Stephen Harper said Friday that his government intends to fulfill an early campaign commitment by holding a free vote on same-sex marriage in the fall.

"It will be a free vote and the vote will be in the autumn," Harper told reporters in Montreal.

The Conservatives, who won the Jan. 23 vote, campaigned on a pledge to allow a vote on whether to reopen the divisive same-sex marriage law. That came in response to complaints that the Liberals rushed the law through last summer.

If MPs approve the idea of addressing same-sex unions, the government would then introduce legislation changing the definition of marriage back to that of a union between a man and a woman.

Liberal MP Keith Martin argued that the country has more pressing matters to deal with and that Harper should get on with them.

"The prime minister has to get over it," Martin said Friday.

"This issue is dead. It's over. The provinces, the courts and Parliament have decided the same-sex marriage is the law of the land."

NDP MP Bill Siksay also said there is no need for another vote.

"The Conservatives are endlessly willing to debate our full participation in Canadian society," the openly gay MP from British Columbia said outside the Commons.

"I think most Canadians have decided that we should be full participants and that the debate should be over."

Although Harper would not comment on how many Conservative MPs do not want to revisit the thorny issue. Reports suggest many Conservatives aren't keen to reopen the debate on gay marriage.

"At this stage, we've debated it pretty thoroughly," Fisheries Minister Loyola Hearn told The Canadian Press last month.

"Once you've reached the optimum, nobody is really happy, but if it's the best that you can do, then it's probably best to just leave it alone."

Trade Minister David Emerson observed: "If it ain't broke..."

"Candidly, I'm not excited about reopening the issue," Emerson said. "Even in the last election, when I ran as a Liberal, it was not a big issue that I was confronted with at the doorstep."

Only three Conservative MPs voted in favour of same-sex marriage during the last House of Commons vote on the issue a year ago: now-Indian Affairs Minister Jim Prentice, James Moore and Gerald Keddy.

On a related note, the prime minister isn't sure whether he will accept an invitation to attend this summer's Outgames as thousands of gay athletes gather in Montreal.

"I don't know what the status of that invitation is," he said Friday. "We haven't got any plans at the moment, but haven't made final decisions for our summer travel."

Canada became the fourth nation to legalize same-sex marriages when the law, which was introduced by the previous Liberal government, was adopted in late June 2005.