A political commentator says National's leader lacks political instincts.

National health spokesman Michael Woodhouse told leader Todd Muller on Tuesday evening that he was also sent Covid patient data by Michelle Boag.

Woodhouse confessed this morning he was sent four unsolicited emails from Boag between June 21 and 25 which contained patient details, but it was not the same information that was sent to disgraced MP Hamish Walker.

A party spokeswoman said today Woodhouse told Muller this on Tuesday night.

But the next day, Muller was specifically asked by reporters "have you checked with Woodhouse, specifically, whether he received that same information from Boag".

"No," replied Muller and a reporter asked "why not?"

"It's very clear from our perspective there's a conversation that's occurred between Michelle Boag and Hamish Walker. We are confident from what we can see that the issue here relates to Michelle Boag and Hamish Walker."

He said it wasn't accurate to say he didn't know whether other MPs in National had access to that information.

"We are confident from what we can see that the issue here relates to Michelle Boag and Hamish Walker ...You've heard very clearly from the participants that the issue was between Michelle Boag and Hamish Walker."

At no point in yesterday's media stand-up did Muller mention that he knew Boag had sent Covid patient information to Woodhouse.

Commentator Ben Thomas says the party leader should have been more up-front.

"Unfortunately probably reflects a lack of character judgement, which are not the sorts of things you want coming into an election."

He told The Weekend Collective that National didn't capitalise on Labour's own mistakes - with David Clark's resignation as Health Minister not forgotten.