Two MPS who plan to vote against their party line on same-sex marriage -- Conservative Belinda Stronach and Liberal Pat O'Brien -- are stressing the need for a free vote in parliament.

"First of all, we have to recognize there is division across the country, there is division within the political parties, and division within ethnic and church groups on this issue," Stronach told CTV's Question Period.

Stronach is among five Conservative MPs who have announced they will be voting with the Liberal government on this issue.

"It's a complex moral and social issue. It's legislation that we have to review very carefully, we have to consult our constituents, and then I think each person has to do some inner reflection on how they're going to vote," she said.

Stronach says she's done all that research and reflection, and has decided to vote in favour of the government's bill, which was introduced earlier this week.

"I believe that Canadians have the right to be treated equally under the charter," she said. "I believe you can't pick and choose when it comes to the Charter of Rights."

She also believes the current legislation supports the freedom of religious groups that don't want to perform same-sex marriage, but if the Conservative Party leadership decides to put forward amendments to strengthen those rights, she will support that effort.

Liberal Pat O'Brien says that while Prime Minister Paul Martin has promised a free vote for his backbenchers, there has been some indirect pressure for MPs to either vote with the government, or miss the vote, expected later this month.

"On an issue of this magnitude, where the PM has promised a free vote, that ought to mean free of any kind of pressure," O'Brien said.

O'Brien said his views are firm and well-know to Martin. "But other MPS are getting pressure from people in leadership in the party," he said. They are being approached by staff of party whip Karen Redman, he said, and being asked to "take a walk."

That's done all the time in Ottawa, O'Brien said, but he feels it's inappropriate "on a matter of this importance."