IN WHAT has been described as a "historical moment" in Australian politics, the Prime Minister, Kevin Rudd, has defended same-sex marriage just days before the federal election.

On a national television programme, Mr Rudd was challenged on his support of same-sex marriage by the pastor of a conservative Brisbane church, who asked why, if he called himself a Christian, he did not believe the words of Jesus. To loud applause from the studio audience, Mr Rudd responded that the Bible also said that slavery was a "natural condition". The human condition and social conditions change, he said, but the "fundamental principle of the New Testament" was "universal love".

Mr Rudd, an Anglican who attends church regularly, then engaged in a spirited discussion about the New Testament with the pastor.

A prominent Australian gay activist, Professor Kerryn Phelps, tweeted that it was "an historical moment in Australian politics". The national director of the advocacy group Australian Marriage Equality, Rodney Croome, commented that it was "unprecedented in Australian history for a Prime Minister to give such a strong defence of equality for gay people, and was made all the more compelling because it was from a Christian perspective".

With the federal election to be held tomorrow, opinion polls currently predict a landslide victory for the Opposition coalition of the Liberal and National Parties, led by Tony Abbott, a Roman Catholic.