Far from modifying her denouncement of gay marriage, tennis champion Margaret Court has broadened it, saying that it was causing huge problems in countries where it was legalised, that homosexuality was an ungodly "lust for the flesh" and that LGBT tendencies in young people were "all the devil".

"That's what Hitler did. That's what communism did," Court said, "get in the minds of the children. There's a whole plot in our nation and in the nations of the world to get in the minds of the children."

In the face of polls that show 65 per cent of Australians support gay marriage, Court said: "We know the statistics are very, very wrong. They're after our young ones, that's what they're after."

Court was speaking on Vision Christian Radio, elaborating on a previous letter to the West Australian and an appearance on The Project in which she said she would boycott Qantas from now on because of chief executive Alan Joyce's backing for gay marriage.