PM coy on respecting plebiscite result

Tony Abbott has side-stepped questions over whether he and his MPs would vote in favour of gay marriage laws if a national vote affirmed public support.

Tony Abbott won't say whether he and other coalition MPs who oppose same-sex marriage will abide by any popular vote that supports a change to existing laws.

"Plainly the whole point of putting this to a peoples' vote... is to settle the matter," the prime minister told reporters in Canberra on Thursday.

He indicated the government would have more to say before the next election about whether it intends to hold a plebiscite or a referendum.