NZ Election 2020: Sir John Key showers Judith Collins with praise, says she's campaigning 'really really well'

Former Prime Minister Sir John Key is dismissing criticism of National leader Judith Collins, saying she's campaigning "really, really well".

It's been a week of campaign woes for National. Earlier this week, deputy leader Gerry Brownlee took exception to a question asked by a Newshub journalist and referred to them as "lazy as buggery".

That was after National spokesperson for local government Denise Lee slammed Collins' plan to review Auckland Council as "highly problematic". Collins did not consult Lee before making the announcement.

Sir John told Newstalk ZB Collins had been "a little bit" let down but didn't think it was a big deal.

"The reality is - I think she's been campaigning really really well. She's had good debates, she's looked confident and strong, she's known her policies, she's on the right issues, I think, in terms of the economy.

"What these stories are and the way we would describe them is they're a process issue and the media love process issues because, frankly, we actually get sick of talking about the issues that people really vote on, so they talk about the little bit of process that went wrong along the way."

Collins was also accused by another MP that she was consistently "making up policy on the hoof". She defended those accusations on Wednesday, telling The AM Show it's common during an election campaign for leaders to change party policy.

Sir John said the debacle wouldn't be held against Collins by voters.

He also reiterated comments he made last week about National Auckland Central candidate Emma Mellow, telling Newstalk ZB she was a "phenomenal candidate" and "the perfect fit".

The latest Newshub-Reid Research poll has National on 29.6 percent of the vote - up 4.5 percent on the previous poll - compared to Labour's 50.1 percent. The most-recent Newshub-Reid Research Poll for Auckland Central meanwhile had Mellow on 26 percent, trailing Labour's Helen White on 42 percent.