Prime Minister Christopher Luxon faces questions in Auckland

Prime Miniser Christopher Luxon has defended his government's record on smoking after new revelations about his Associate Health Minister's communications with officials.

Luxon is facing questions from media during a trip to Auckland.

He was asked about RNZ's revelations that notes New Zealand First Minister Casey Costello sent to health officials on reforming smoke free laws made it clear a freeze on excise tax for tobacco was her idea.

Luxon said he hadn't seen the papers, however, the government increased excise tax on cigarettes in December.

"We did that incredibly quickly."

He repeated his earlier stance that Costello was determined to reduce smoking rates around the country.

"I've spoken to her about it, she's passionate about it, she cares about it, I've got confidence that she wants to do that," he said

"She maybe asked for a broad range of advice and feedback [from officials] ...all I can tell you is excise tax has gone up, it's been implemented, it's happening."

Asked if Costello was the right person to be the Smokefree Minister, he replied the government's smokefree position was being "very poorly misrepresented".

The existing legislation had seen daily smoking rates fall from 16.7 10 years ago to 8.6 and, then fall another two points.

Pressed again on Costello's role, all Luxon would say was she was very determined to assist the 6.8 percent of Kiwis who were still daily smokers.

"We know it gets harder, but she's asking for advice on education ...She's very determined to reduce smoking rates across New Zealand."

He said he was not responsible for every request a minister maked

"I'm clear about the priorities I'm asking them to deliver. I'm clear about the delegation. I've been very clear about that, probably more clear than any previous prime minister".

Asked about ministers declaring any donations they had received from the tobacco industry, Luxon said there were "incredibly good" disclosure and conflict of interest rules.

The other two minor parties had told him (via staff) they had not received money in that regard.

Every Cabinet meeting started with ensuring there were no perceived or potential conflict of interest issues that needed to be raised.

"I think we've got a very robust conflict of interest process," Luxon said.

He agreed it would not be desirable to have a tobacco lobbyist writing a tobacco policy. However, politicians needed to make themselves available to people from a range of sectors for conversations, he said.

"That is not code. That is not an excuse that the tobacco industry should be inputting deeply into your policy development."

Luxon and Erica Stanford have been at Browns Bay School on Auckland's North Shore.

Luxon said his school visit was due to the fantastic things happening under the guidance of its principal, who is due to retire shortly.

He appealed to parents nationwide "to do the right thing" with sending their children to school and said the government was doing its part with requirements for teaching maths, reading and English and the ban on cellphones.

It comes after Parliament resumed in Wellington for the New Year this week.