It's been a huge few weeks in politics, and for Labour in particular.

But what are the issues behind the headlines?

Newstalk ZB's Mike Hosking this morning grilled Labour leader Jacinda Ardern on her party's policy plans - and how to fund them - after yesterday's Treasury pre-election update.

First topic up was New Zealand's involvement in Afghanistan.


Ardern says she wouldn't back sending troops to the conflict-ridden country at the moment, but added that such decisions were based on United Nations requests and other intelligence that she wasn't privy to.

"I'd want more information but currently no," she told Hosking.

She also said personal tax cuts were off the table, which meant there was money to fund Government spending.

"We already said we wouldn't vote for tax cuts so that frees up a lot of fiscal headroom for us to deliver our programme - that's the major difference in our spending programme between us and National."

Ardern denied a Labour-led government would bring in a capital gains tax but said a working party would examine the situation after the election. However, family homes remained off the table, she said.

"We've got a housing crisis and we have to act."

On coalition with New Zealand First, Ardern said Winston Peters would not be in charge of the Treasury benches.

"The finance role with stay with Labour no matter what, no matter whom we're in coalition negotiations with," said Ardern.

"Both major parties will be looking around for coalition partners after this election - that's absolutely clear currently. There will still be a lot of movement in the polls I'm sure but right now both parties are facing this issue," she said.

Yesterday's Treasury update showed an initial bump in economic growth and spare cash for the incoming Government, followed by several years of lower-than-expected growth, lower surpluses, and less cash.

She said debt repayment under a Labour-led government would take an extra two years, compared with the current timetable.

Ardern has already raised the possibility of taxes on commercial water use, but hadn't set rates on water taxes before talking to the affected communities.

"Our waters are dying and we have to do something about it. And I'll also tell you we have to deal with water bottlers," said Ardern.

"We haven't set a rate is because I want to sit down with everyone affected by this.

"I refuse to say we're just going to burden you with this without talking to you about the range, how it will work."

She said she grew up on an orchard that exported for a few years so she had some understanding about the issues horticulturists and farmers were raising over the proposed tax, which may be a two-tiered rate depending on what the water is being used for.

After becoming leader, Ardern said she wanted to put more emphasis on investing in health, social and education investment.

Hosking will also be talking to Ardern about the Green Party's surprise 11th-hour decision to stand a candidate in the hotly contested Wellington seat of Ohariu - and what that means for Labour.

Tane Woodley made the surprise revelation on Wednesday night.

The decison follows the shock departure of 33-year incumbent Peter Dunne.

Green Party co-convenor Debs Martin said Woodley would be "vigorously campaigning for Party Vote Green" in the electorate.

Labour Party general secretary Andrew Kirton said the Greens informed Labour on Wednesday afternoon that Woodley was standing, "which is consistent with our Memorandum of Understanding".

"It was actually not unexpected - we have a friendly contest for the party vote."

He said it had been entirely the Greens' decision not to stand a candidate this year and they had no agreement with Labour on the matter.

Kirton said nothing would change for O'Connor, who when Dunne stepped down said he wanted to focus on being "the best candidate possible to become a good MP like Peter [Dunne] was. Nothing changes there."