US President Barack Obama's announcement that he supports marriage rights for non-heterosexual couples has sparked a row over numbers in Australia.
Community advocacy group GetUp says a US Gallup poll showed that 49 per cent of American voters support marriage rights for non-heterosexual couples, compared to 62 per cent in Australia.
"There's more support here in Australiafor marriage equality than there is in the US," said GetUp's national director Simon Sheikh.
"The PM needs to shift her position into line with the broader public," he added.
"It's only parliament we're waiting for," he said, stressing that British Prime Minister David Cameron had also declared his support for the cause.
Those numbers were incorrect, according to head of the Australian Christian Lobby Jim Wallace.
"This is typical GetUp nonsense," he said, adding that there were only 10 countries around the world where gay marriage was recognised.
A referendum this week in North Carolina had fallen 61-39 against allowing non-heterosexual couples to marry, he said.
"Every time this has been voted on the US it's been defeated," Mr Wallace said.
"That's 32 times," he added.
"And that's because the average person doesn't believe that a marriage is other than between a man and a woman. It's a biological truth," he said.
Mr Wallace did not think President Obama's announcement that LGBT people should be treated equally with regards to marriage would have any effect on Australian politics.
"The reality is this is the opinion of the President of the United States, and even the President of the United States can't change biolgical reality," he said.