Former Australian Idol contestant Anthony Callea has slammed the upcoming same-sex marriage survey, labelling it "insulting" on national television.

While appearing on Channel 10's The Project to promote his seventh album, Callea was asked for his thoughts on the federal government spending millions of dollars of taxpayers' money to hold a non-binding postal ballot. The singer married his partner - actor Tim Campbell - in New Zealand three years ago.

"I honestly feel that this whole situation is just insulting," he said. "I don't think we should be voting on a human rights issue. Religion's got nothing to do with it, families have got nothing to do with it. Essentially, we just want a law to be equal." 

The studio audience then erupted into applause. 

"Tim and I have been together for about 10 years now and we didn't want to wait for our government to tell us that we can get married," the singer continued. 

"So we went over to New Zealand and we did it when we wanted to do it. It would just be beautiful to have our marriage recognised in our own country, because it's such a great thing when we go to Europe and we go to LA that our marriage is recognised - but in our own country, where we wake up every day, it's not." 

Callea has been advocating for marriage equality on TV and radio over the past 24 hours off the back of his new album ARIA Number 1 Hits in Symphony.

The album features Callea performing 12 number one songs from the ARIA music charts in collaboration with the Melbourne Symphony Orchestra. 

He will perform the album live for the first time with the orchestra on Friday night at Hamer Hall.