Thousands of flowers have been placed in front of Parliament House from Australians who want to thank Tony Abbott for standing by traditional marriage.
But the prime minister was unable to personally accept their thanks.
The gesture was organised by the Christian Federation, which has called for a civil conversation on changing the Marriage Act.
"There are millions of Aussies who very much feel in their heart the best way to raise children is with a traditional mum and dad," executive director Peter Kentley told AAP.
The way marriage is now is pretty good, the federation believes.
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"No one's being discriminated against with civil unions and de factos," Mr Kentley said.
Family First senator Bob Day, who greeted the organisers, said it was refreshing to see an innovative and "nice gesture" instead of a gimmick.
If there was a referendum over the issue he predicts the public would vote no.
But the sea of floral colour on the forecourt is different to the rainbow lights greeting MPs flying into Canberra for the return of parliament.
The capital's terminal also had a giant #WeCanDoThis campaign sign out the front.
Opposition Leader Bill Shorten's same-sex marriage legislation will get 10 minutes of debate in parliament on Monday evening.
Liberal backbencher Warren Entsch is expected to give notice of a cross-party bill which is unlikely to be debated for at least a week.
