National Party leader Judith Collins says Winston Peters' description of the party as "sex maniacs" shows that the New Zealand First leader "obviously doesn't know us".

But she has drawn the line at the use of the f-word to respond to Peters, with her office telling Kaipara Ki Mahurangi MP Chris Penk to remove a tweet that said: "Winston Peters is the real s*x maniac because he can f**k a whole country at once."

Peters made a speech at New Zealand First's AGM on Sunday in Auckland, declaring that his party will be back in 2023.

Yesterday he told Newstalk ZB that he would lead the party in the 2023 campaign if the party wanted him to, and if he was fit and motivated.

NZ First leader Winston Peters says his decision in 2017 not to go with the National Party has been vindicated because of 'the mess they're in now'. (Photo / Dean Purcell)

He felt vindicated for not going with the National Party in 2017, he said.

"You look at the sex maniacs and the mess that they're in now and tell me, what option did I have?"

It was unclear who Peters was referring to, but former MP Andrew Falloon and former candidate Jake Bezzant have both been accused of inappropriate sexting.

Penk tweeted in response, but his tweet has since been removed.

Asked this morning about Penk's use of the f-word in his tweet, Collins said "it's not a term I'd use".

She did not think the tweet was funny.

"My office said it's just simply inappropriate. We don't use that sort of language."

On Peters calling the party "sex maniacs", Collins said: "Yeah. No ... he obviously doesn't know us."

Collins wouldn't specifically rule out working with Peters in any future coalition.

"I don't think it's going to become an issue because I really don't see it coming back.

"It's an extraordinary hypothetical. And the party's always ruled him out for years now, and there doesn't seem any reason to me why we wouldn't continue that."

Asked if she could work with New Zealand First under a different leader, she said: "We'll wait and see."

National Party MP Chris Penk has removed a tweet about Winston Peters that Judith Collins' office said used inappropriate language. (Photo / Derek Cheng)

Prime Minister Jacinda Ardern said it was a "very big hypothetical" to say whether she would work with Peters in 2023, but she has demonstrated that she can work with him and get "good things done".

Peters accused Labour of withholding the He Puapua report from the four New Zealand First Cabinet Ministers last term, but Ardern rejected this, saying "that's not my recollection".

Māori Development Minister Willie Jackson said if it was withheld, it wasn't intentional, adding that in retrospect he's glad NZ First never saw it as "they would have tried to utilise it".

New Zealand First were part of last term's Coalition Government, but failed to return to Parliament after only winning 2.6 per cent of the vote last year.

Peters used his speech at the AGM to also attack Labour, National, the Greens, the use of the word "Aotearoa" instead of "New Zealand" in government reports, the Auckland cycle bridge, Auckland light rail, the vaccine rollout and "Ngāti Woke".

Party members at the conference told the Herald there was too much focus on the negative and the policies that the party had been a "handbrake" on, and not enough on what it had achieved.

Peters didn't traverse the party's review into what went wrong last year in his speech, but said there was a growing sentiment among the public that the Government needed NZ First.

"We were pilloried for being the handbrake, but since the last election hundreds of thousands of New Zealanders are coming to understand why we were essential and now why we are missed."