National leader Simon Bridges said NZ First leader Winston Peters needed to develop a thicker skin if he was taking criticism of him at a National Party conference so seriously.

Peters has bridled at comments by former Australia Prime Minister John Howard that the election outcome was "unjust" and by National Party President Peter Goodfellow that National "dodged a whisky-swilling, cigarette-smoking, double-breasted and irrational bullet."

Bridges said after 40 years in politics, he would have thought Peters had a thicker skin.

On Monday, Peters had appeared to threaten Goodfellow, saying he should repeat the comments and Peters would reveal why he did not believe Goodfellow should be the president.

Today Peters asked if Goodfellow had repeated that and when told no, said "guess why." He would not say if he had something on Goodfellow.

"I'm not going to have a duel of wits with an unarmed opponent no matter how wealthy he is."

In response, Goodfellow said he was not aware of any "dirt" Peters might have on him and noted he had not mentioned Peters by name at the conference. He laughed when asked who else he could have been referring to.

Asked if he would repeat the comments, he said "why would I? How many times do you have to say it?"

He remembered working for Peters when Goodfellow was a Young Nat and Peters was standing in Hunua and suggested Peters was thin-skinned.

Peters had said Howard was interfering in domestic politics for his comments about NZ First opting to go with Labour rather than National after the election.