Ron Mark says National leader Simon Bridges talked to him about a deal during a flight earlier this year, contradicting Bridges' claim no such approach was made.

"It's true. Simon and I were next to each other on a flight from Auckland to Wellington in May. He bought it up out of the blue during a conversation we were having.

"He was just sounding me out about a deal in general, involving the Wairarapa. He didn't get into the specifics of what that might look like. I laughed it off before he could go any further.

"New Zealand First doesn't do deals, so I didn't entertain the thought further," Mark said in a statement to the Herald.

Bridges today dismissed as "fake news" a claim by New Zealand First leader Winston Peters today that the National leader had tried to talk his MPs, including Mark, into leaving the party.

Peters was speaking to Newstalk ZB today about a clause in the New Zealand First constitution which essentially binds MPs to the party with a $300,000 penalty if they resign or are expelled and don't leave Parliament promptly.

"The leader of the National Party Simon Bridges has been talking to members of my caucus about how they might jump the ship and stay on, doing a deal with them. This is how bad and how rotten it is," Peters said.

He named Mark as a target of Bridges' approaches.

"[Bridges] has been witnessed saying 'look come on Ron, let's just do a deal. You can have Wairarapa'. In short he was talking about dumping his local MP called [Alastair] Scott. So, you know, pretty bad stuff."

Bridges denied he had made any such approach to any NZ First caucus member.

"This is yet more fake news from Winston Peters. I don't think I've even had a conversation with Ron Mark this year let alone made any suggestions to him. Winston should be focused on things that matter to New Zealand instead of distractions and sideshows."

Bridges said Scott was a hard-working member for Wairarapa. "I intend to keep it that way."