Justice Minister Irwin Cotler says there will be no national referendum on same-sex marriage.

Cotler says if a referendum had been held to decide whether women were entitled to vote when the franchise was extended to them, women would have likely lost. He says a national vote won't protect minority rights.

Some Liberal MPs say they are feeling pressured to accept the bill.

Irwin Cotler (File Photo)

Backbench Ontario Liberal MP Pat O'Brien has been trying to drum up interest in a referendum. He says Liberals opposed to the legislation are being told to consider staying away from the House when it comes to a vote.

Meanwhile, three more Conservative MPs say they will support the same-sex legislation.

Gerald Keddy, Jim Prentice and James Moore will join with Belinda Stronach, who has already made her position clear, in voting with the Liberals.

"These are the modern liberties of our Western society. They are the very liberties that underpin Western society, and they are owed to each of us equally and unconditionally," said Prentice in a statement.