Experts doubt tonight's Ardern versus Collins match-up will shake up the polls much.
The election campaign's first leaders debate will be on TVNZ at 7pm.
Auckland University politics lecturer Lara Greaves told Kate Hawkesby it's usually only around ten percent of voters who make up their minds this late in the campaign.
"Labour has been doing so well in the polls. I don’t think the debate performance will make a huge difference,
“It would have to be a horrible performance from the Labour leader and a great one from her National counterpart to sway the polls at all."
Greaves says between 700,000 and a million people are expected to tune in.
She says it's a great chance for leaders to get their ideas out there and show their personalities - but in the social media age there's also a risk.