Water's a divisive issue - and one at the centre of the election campaign on Thursday.

New Zealand's water quality issues have just made international headlines, and Greenpeace protesters have been arrested after occupying a Canterbury irrigation dam.

A Newshub-Reid Research poll shows that Kiwis are split on Labour's wide-ranging tax on commercial water users - and National's plan to keep it free.

Sixty-two percent say yes to a tax on commercial water users, and 32 percent say no.

But when you break it down only 33 percent want it on all commercial users like farmers and growers.

That's because 28 percent say they want it only on water bottlers.

The parties are also divided. National says no to a tax.

"We don't think a tax is the way to achieve higher water quality," says National Party leader Bill English.

Labour and the Greens say yes. New Zealand First only want one on water bottlers.

This means NZ First leader Winston Peters' position is closest to what the poll says, which is tax bottlers not farmers.

But Mr English is sounding a warning that putting a tax on water will mean Māori will claim it.

"As soon as someone puts on tax on water Māori will claim it, we've always said no one owns the water," he says.

Mr English's argument that a tax would mean Māori would claim water has him creating a real wedge between Māori and Pakeha on the issue.

The poll shows the public is divided on it - so too are the politicians.

Newshub.