Day four of the election campaign and the National Party is facing questions about its campaign slogan making an appearance at yesterday's pre-election fiscal update at Treasury.

Photo: RNZ / Rebekah Parsons-King

The party's leader, Bill English, said the State Services Commission (SSC) would investigate whether it was appropriate to use a party slogan for government business.

"Delivering for New Zealanders" is the official National Party election campaign slogan, and also featured in the Finance Minister's slide show briefing at Treasury.

State Services Commission rules require government departments to stay clear of party politics in the run up to the election.

Mr English said the pre-election update was a follow up to the May budget, which also featured the slogan.

"Delivering for New Zealanders was a tagline of the 2017 Budget, so it's right through the Budget material which was certainly a government announcement.

"The PREFU [Pre-Election Economic and Fiscal Update] is essentially a budget process and the Treasury run it, and it looks like the Budget material, so the SSC can have a look at it, quite happy to take their advice."

The States Services Commission said in a statement that it had been asked to comment on the slide show briefing at Treasury.

"Following our standard process SSC is engaging with the Treasury to better understand what happened in this case," said the statement.

The Labour Party said it was the third time National had failed to observe the rules.

According to Labour's campaign chairperson, Phil Twyford, National launched their transport policy on an Auckland Transport rail platform without permission.

They also announced government policy on the rebuild of Dunedin Hospital as a National Party election campaign announcement.

Mr Twyford said these "hiccups" were "getting to be a bit of a habit".

"I would have thought they would have been very familiar with the rules."

"Given that we've now got a pattern of the National Party blurring the boundaries between when its speaking as the elected government of the day and when its speaking as the party's election campaign, I think it's probably worth taking a serious look at it."

Afghanistan decision?

Mr English also fielded further questions about New Zealand's continued involvement in Afghanistan.

He was also asked about what information he would give to Labour about a request to send two more non-combat military personnel to Afghanistan.

Mr English said Cabinet had already made the decision, and he was quite happy to share details with Labour's leader.

"As requested we'll make the information available. But I can assure them and everyone else that it involves non-combat."