OTTAWA — Opposition Leader Stephen Harper's office defended a policy Monday of asking to see Conservative MPs' speeches on same-sex marriage before they're delivered in the House of Commons.

It is necessary to ensure that arguments made on either side of the issue by Conservatives are clearly focused on the definition of marriage and nothing else, said Harper communications director Geoff Norquay.

The history of members of the former Canadian Alliance to grab headlines with outbursts on social issues such as gay rights and women has been widely documented.

Harper's decision to preview what MPs will say during debate on same-sex marriage legislation would limit fresh controversy, but Norquay would not comment.

"Prudent MPs come to us all the time for communications and policy advice and that's what we're doing,'' he said.

British Columbia MP James Moore, one of a handful of Conservatives who say they will vote with the Liberal government to allow same-sex marriages, said he was somewhat concerned by the move.

"Well, to some degree, but this is a very divisive debate, emotions are running high on both sides on both extremes and I think that Stephen Harper and the leadership are ensuring the debate is civil and respectful,'' he said.

Moore said he doesn't plan to speak during debate.

Norquay said the Opposition Leaders Office had not heard any complaints about the policy from members of the Conservative caucus.

The Liberal bill, to be debated starting Wednesday, would legalize same-sex marriage across Canada.

It's expected to pass with support from most Liberals, Bloc Quebecois and New Democratic Party MPs. Veteran MP Diane Ablonczy said her leader is not muzzling members.

"That's not what it's intended to do,'' she said. "It's just to get a sense of where people are coming from and to make sure all the aspects of the debate are covered.''

"That's been done before where you have a major debate. You just want to make sure all the bases are covered,'' she said.

MP Brian Pallister indicated the vetting would avoid a polarized view of the issue.

"We've got to get beyond this . . . one side accusing the other of homophobia and the other side saying the other side is going to burn in hell,'' he said.

"We have to talk about this sensitively and that's what we're doing in caucus.''

The policy may pose a problem for Myron Thompson, who said he's never written down a word he's spoken before delivering them in the House of Commons.

"I don't know how I'm going to handle that yet because I've never written a speech in the 12 years I've been here, I usually speak from the heart, so I'll have to think about that awhile,'' he said.