Police say they are making inquiries into businessman Harry Mowbray's Split Your Vote website.

Detective Senior Sergeant Andrew Compton said they had received a referral from the Electoral Commission in relation to Mowbray's campaign.

It encourages National supporters to give their party vote to Act or New Zealand First in an attempt to create an overhang and potentially make it more likely the coalition parties can form the next government.

Det Snr Sgt Compton said they were now making inquiries and no further comment could be made at this stage.

Mowbray, a wealthy businessman whose children Mat, Nick and Anna Mowbray founded the toy company Zuru, recently had to take down the website after the Electoral Commission contacted him raising several issues related to the laws that govern electoral advertising.

The website had been put back up, and Mowbray told The New Zealand Herald on Monday it had been tweaked with the hope it aligned with the law.

National has pushed back against Mowbray’s campaign, and confirmed late on Friday afternoon it had complained to the Electoral Commission about the website.

On Tuesday morning, Prime Minister Christopher Luxon wouldn’t be drawn on the issue.

Asked in Marlborough what he made of police investigating, he said he didn't want to get into it.

"I've talked about that. You know, the strategic voting campaign over the last few days. I've got nothing further to say, and frankly, now that it's a matter before the police, I'll leave it there."

— additional reporting ODT Online