Winston Peters has come under attack by one of his five outgoing MPs - the morning after he used his election speech to warn colleagues off saying anything that could embarrass the party.

NZ First MPs Richard Prosser, Mahesh Bindra, Denis O'Rourke, Pita Paraone and Ria Bond are all out of Parliament based on the preliminary result.

Three candidates ranked higher on the party's list will be on their way to Parliament - Southland sheep farmer Mark Patterson, former newsreader Jenny Marcroft and former Labour MP Shane Jones.

Prosser is now thinking about doing some broadcasting after a dramatic drop from third on the party list to 15th meant he was effectively shown the exit door.

Advertisement

He told the Herald whoever negotiated with Peters in the coming days and weeks might need to deal with what Prosser called examples of erratic behaviour.

"He has always been Machiavellian, I guess, and a bit mercurial. And sort of says things in a way that leaves wriggle room. This goes beyond that. These are things when you just think, what on earth is happening?"

Prosser gave examples of recent behaviour including Peters saying he had discussed with caucus the idea of withholding tax refunds from men who didn't have regular prostate health check-ups.

NZ First president Brent Catchpole did not respond to a request for comment on whether outgoing MPs would play any part in coalition discussions.

But Prosser said Peters would essentially make the decision himself, and any notion of consultation was "a myth". He believed Peters would go with Labour and the Greens if at all possible.

"The simplest thing and obviously what the country wants is for him to just sign up with National and just get on with the job of forming Government.

"But the nation has obviously indicated a mood for change, and if he can capitalise on that as well there is a lot of utu to go on with him and the Nats."

Asked what concessions Peters might push for, Prosser said it would "be more around baubles than policy".

"Because the policy goals that are most important to NZ First supporters are anathema to the Nats. And he won't get those - restrictions on foreign ownership . . . restrictions on immigration, he won't get any of those. There may be some minor bits and pieces."

Paraone said he was feeling disappointed personally but happy for the party to be in the position it is in now.

"My view is we have a responsibility to do right by those people who supported us."

Paraone acknowledged the experience of the outgoing MPs.

"That might be the thing that caucus will certainly have to face given the experience of those who missed out."