The Australian musician, who is in a relationship with former Home and Away actor Tim Campbell, joined the gay rights debate initiated by Lady GaGa when she visited Sydney earlier this week.
Callea told the Herald Sun: "I just think whether you want to or not, the choice should be there. It's about having the same rights as anyone else and I think it's great what New York has done. Hopefully we'll follow soon."
He also said that he was pleased Lady GaGa had visited Australia, saying: "You can either love her or hate her but she's brought excitement back. We need that. It's getting to the point where everything is quite formulated and there's someone who is not afraid to do what she wants. It's quite refreshing."
Callea now guest presents Joy FM's breakfast show with Campbell. He said that it is a "lot of fun", especially because he can "do it with someone [he] lives with and knows".
When Lady GaGa brought up the gay marriage issue earlier this week, she said: "It's 2011, get on with it. I am so against the way certain laws and restrictions send messages that one person is better than another. I urge all of you to mobilise your voices so the prime minister can hear you scream that you want to be equal."
Last year, Lady GaGa said that she wanted to get ordained so she could perform marriage ceremonies for her gay fans. She also hosted a gay rights gala in the US calling for same-sex marriage to be legalised.
Watch Lady GaGa's 'Born This Way' video below: