Jacinda Ardern won't be banning minsters from having sex with staff members because, she says, they already have clear expectations around conduct.

"My expectation is my ministers already have a clear sense around my expectations around their behaviour and that cuts across a wider area," Ms Ardern said during her weekly post-Cabinet press conference.

"I do not believe at this time that's the kind of thing necessary for our New Zealand ministers," Ms Ardern said.

The questions surfaced after Australia's Prime Minister Malcolm Turnbull imposed a ban on sex between ministers and staffers last week. The ban followed revelations Deputy Prime Minister Barnaby Joyce had an affair with a former staffer.

Mr Joyce, the leader of coalition partner National Party, is expecting a child with his new pregnant partner.

The ban on sex was quickly dubbed the "bonk ban" on social media - a nickname picked up by traditional media in Australia.

The ban attracted international headlines but more damaging for the Australian government is the war of words between the coalition partners.

Mr Turnbull said Mr Joyce caused a "world of woe" for his wife and four daughters, and said the affair "appalled everyone".

Mr Joyce returned fire, saying Mr Turnbull's comments were "inept and most definitely in many instances unnecessary".

"All that is going to do is basically once more pull the scab off for everybody to have a look at."

Both parties are now attempting to smooth the public rift.

Newshub.