The Labour-Green partnership hasn't been damaged by going head-to-head in the Mt Albert by-election.

That's according to Labour leader Andrew Little, who said the top tiers of both parties haven't changed their relationship during the campaign.

Mt Albert Labour candidate Jacinda Ardern said their competition has only been highlighted because there's no National candidate.

"It's not going to be unusual for Labour and the Greens to both have candidates and seats at a general election and it wasn't unusual that they choose to use the opportunity of a by-election to put forward what their party stood for, as we have."

Meanwhile, polling day for tomorrow's Mt Albert by-election is predicted to have a very low turnout.

Ardern told reporters she's predicting even her own supporters won't turn up to the booths in great​ numbers.

She said some Labour supporters won't vote because they believe she already has victory in the bag.

"There's certainly been a lot of people who have voiced strong support, but at the same time have felt that weather they voted or not wouldn't necessarily make a difference to us taking the seat."