The Prime Minister should deal urgently with reports Cabinet Minister Kris Faafoi offered to help a friend over an immigration case, National Party leader Simon Bridges says.

Photo: RNZ / Dom Thomas

Newshub reported it has seen texts and Facebook messages between Mr Faafoi and Jason Kerrison, whose stepfather's partnership visa application had been declined. It said Mr Faafoi told the Opshop band member he would "talk to the people that can speed things up", Newshub reported.

It was not known if Mr Faafoi took any steps to intercede.

National Party leader Simon Bridges told Morning Report if the texts were proven it would be a conflict of interest and may breach Cabinet rules.

Mr Faafoi declined to comment to RNZ, but told Newshub he thought Mr Kerrison had a genuine case so he offered to speak to his local MP.

Mr Bridges said it would be entirely appropriate to pass on the case to a local MP, but doing any more would not.

"[The prime minister] needs to show leadership she needs to deal with this urgently. It wouldn't be a difficult case to get to the bottom of very quickly. Faafoi should be asked what's gone on and then deal with it.

"The prime minister herself said Cabinet ministers must uphold the highest ethical standards at all times."

"If it's proven, under a government I lead he'd have to be gone because if you don't do that you're lowering the standards from where they've been in the last 30 or 40 years."