Federal Nationals MP Mark Coulton says support for marriage equality within youth ranks of the Nationals is unlikely to prompt a shake-up in his party.

The New South Wales branch of the Young Nationals says it is the first youth division of a conservative party to support same-sex marriage.

The Member for Parkes Mark Coulton says he is not surprised by the push because the issue is a passionate one for younger people.

But he said he was confident the majority of his electorate supported the traditional marriage position.

"I suspect that the Nationals branches are probably more conservative than the average of my electorate if that makes sense, and so I would think that most of the members in the Nationals certainly sit in the place that I do, but I still am fairly confident that I represent the majority of the people in the Parkes electorate.," Mr Coulton said.

He said he agreed with the Prime Minister Tony Abbott, that a plebiscite was needed.

"To have a position that represented everyone in my electorate would be difficult but I firmly believe that at the moment I represent the majority of the people that I represent.

"I think the fairest way to do this would be to go to a plebiscite, so that everyone in Australia can have a say and it will be in the hands of the people."