New Zealand First leader Winston Peters is defending a party ad blaming the sinking of a navy ship on "woke b******t", but is at odds with his own candidate.

Peters says it's "clear as daylight" the captain of the ship was hired through a diversity, equity and inclusion (DEI) programme.

The ad, posted to social media, shows party candidate and former defence minister Ron Mark saying "woke b******t of diversity, equity and inclusiveness" had gone "too far" and the sinking of the HMNZS Manawanui off the coast of Samoa was "evidence of that".

It also comes as the New Zealand First leader has yet again cautioned his supporters against "wasting" their party vote by party voting National at a packed public meeting in Levin, and as National dropped three points in the latest 1News Verian poll, while New Zealand First gained two.

Mark told RNZ on Tuesday afternoon he took offence at suggestions the social media ad was sexist because the vessel was captained by Commander Yvonne Gray, stating she had a "strong defence" and more focus should be put on the "men who made certain decisions".

However, speaking to media on Tuesday evening, Peters said it was "clear as daylight" that Gray was hired under a "DEI" programme.

Asked if he had evidence of that, Peters replied: "Yes".

"We are not against the promotion of seriously qualified women - never have been - but in this case, she was not qualified.

"To think it was reef examining on autopilot is just appalling and there's no excuse for it. We're against DEI in terms of employment criteria. It's just wrong," he said.

National leader Christopher Luxon said it appeared Mark was trying to "cosplay Pete Hegseth" but did not rule out having him as defence minister in a government he led.

NZ First candidate and former defence minister Ron Mark. Photo: RNZ

Peters said Luxon should spend more time "examining the enormous cost" of the sinking: $100 million.

"When you find that someone was there not qualified to be in command of that ship, I don't care what the background is, we are going to be accountable, and we're going to say so.”

Peters defended Mark, saying he was only pointing out that when you "interpose a criteria that's irrelevant" to the job or task, "this is how these things happen".

Peters had spoken to a packed school hall in Levin, with about 300 people in attendance, where he also announced the party's 10-point rail plan policy that built on work already underway.

He discussed a range of issues, getting rounds of applause when he reiterated leaving the Paris Agreement, and that the country's name was "New Zealand".

There was plenty of interest in discussion around the advice - from the Covid-19 Vaccine Technical Advisory Group - that said a two-dose schedule for the Pfizer vaccine "may add an unnecessary risk of myocarditis" for children under the age of 18.

He also reiterated his concerns about immigration, saying people should "beware ... because what you're seeing offshore could happen here unless we have a focused immigration policy right here, right now".

He said it wasn't racist but "totally patriotic".

STRATEGIC VOTING

Peters began his speech acknowledging the electorate's experience in strategic voting, before getting his own message across, which he wanted his voters to think "seriously" about.

He explained that if a party was entitled to 20 percent of parliament's seats through the party vote, but the party already had 20 percent by way of electorate seats, "then your second vote is sadly, alas, a waste of time because it's not going to be getting you any more MPs".

Speaking to reporters afterward he said the "peculiarity of MMP" meant "a lot of some parties' votes are going to go terribly to waste".

"That's not the voters' purpose. So they need to be informed properly of where they can best make their vote count."

Asked to clarify who those votes would be wasted for, Peters wouldn't specify, but when asked about National's polling, said the National party had more than its party percentage in its electorate seats, "so every vote for the party is sadly a wasted vote".

"The reality is we're talking about a mathematical equation that has a unique peculiarity in this election and not like any election before."

He used an octopus to describe the political landscape, and the nature of political decision-making, suggesting that if there were eight arms, all should be examined.

"The trouble with political commentary at the moment: they're examining about one or two.

"There's many other permutations."