The Labour leader will visit Palmerston North, the electorate of her former immigration minister Iain Lees-Galloway, who resigned two months ago after a workplace affair.

While there, Stats NZ will release economic growth figures for the June quarter - a stretch the country spent largely in lockdown - which will confirm New Zealand's worst recession in recent memory.

And yet, Ms Ardern is still tipped to win on October 17, and possibly in a landslide.

According to public polls, Labour has been heartily rewarded for its health-first approach to COVID-19, which eliminated the virus from the community before a smaller resurgence last month.

The 40-year-old's stratospheric popularity means Labour is in with a fighting chance to become the first party in New Zealand's modern electoral history to govern in their own right, without support parties.

Labour's minority coalition partners - the centre-right New Zealand First and the left-wing Greens - are two of the victims of Ms Ardern's runaway support.

They are both in a fight for campaign cut-through, needing to win at least five per cent to be returned.

Still-fresh opposition leader Judith Collins leads a National party well adrift in the polls, but has been putting her best foot forward in recent weeks.

Ms Collins has hammered the government over its border regime which allowed the recent Auckland cluster, which has seen 178 people contract COVID-19 and three deaths.

National has also drawing attention to growing government debt.

Treasury's major pre-election report, released on Wednesday, projected 15 straight budget deficits due to the COVID-19 recession, with borrowings peaking in four years at $NZ201 billion ($A185 billion) - over half the economy.

Treasury also projected a whopping 16 per cent GDP contraction during the June quarter, which would be the country's worst on record.

That number will be predicted on Thursday, as Ms Ardern makes her first campaign visit of the day.

Australian Associated Press