A NSW gay couple say they oppose same-sex marriage and they want to preserve "traditional" marriage.

Ben Rogers and Mark Poidevin from Wollongong say while they have commited their lives to each other, they don't feel they need to have a legally binding certificate to show it.

The couple met 15 years ago on Gay.com and say they want to preserve the "traditional" definition of marriage between a man and a woman.

“If we make one exception for one community, that being the same-sex couples, where does it stop?” Mr Poidevin told ABC's 7.30 program on Monday night.

View photos Ben Rogers and Mark Poidevin say they don't want to get married. Source: Facebook More

Mr Poidevin, a Catholic, said it could be Australia's "Trump moment" if the vote goes ahead.

“This could be the Brexit or Trump moment for Australia, where the polls are saying one thing but you go to the ballot box and people are clearly in another mind, going to vote another way,” he said.

Mr Rogers said he has already made peace with not being able to get married.

“There’s never been any discrimination with any of our families, or dramas coming our way because of our sexuality,” he said.

“When I first came out I think one of the consequences was giving up marriage and children and things like that.”

Mr Poidevin said he had previously been a supporter of same-sex marriage but Mr Rogers convinced him otherwise.

“I just explained to him, ‘I don’t think it’s my cup of tea,’” Mr Rogers said.

“It’s not something I had ever envisioned.”

View photos The couple say they don't need a marriage certificate. Source: Supplied More

They also spoke about how both camps in the same-sex marriage debate have started to get "nasty".

“The campaign’s gotten nasty on both sides and I think the comments that I hear are, ‘You’re a homophobe if you don’t support gay marriage’,” Mr Poidevin said.

“I’m a gay person here that’s coming out and saying, ‘Well, no it’s not. It’s your right to have a view, your right to have a view either way and people should be respected.’

“You’re not intolerant if you don’t support a view.”

Many social media users have slammed the couple with some saying "it's fine" if they don't want to marry but they "shouldn't support no one being able to get married".

View photos

Story continues