National's chances of working with NZ First weakened by donation allegations - Simon Bridges

The Electoral Commission is looking into New Zealand First and the secretive New Zealand First Foundation following allegations more than $300,000 in donations appears to have been hidden through the fund.

New Zealand First leader Winston Peters is adamant that neither he, his party nor the foundation have done anything wrong, but Simon Bridges says it weakens National's chances of working with NZ First in the future.

The New Zealand First Foundation officially loans some money to the party. But a Stuff investigation is alleging it does much more than that, reporting that it's seen documents showing at least 26 donations to the foundation totaling $325,900.

It allegedly spent the money on party expenses like hiring boxer Joseph Parker to speak at a party conference, travel and legal expenses for NZ First MP Clayton Mitchell, the party's website and donations platform, and a day at the races.

There were a lot of questions about the secretive foundation on Tuesday but not a lot of answers were given.

"You can try your obtuse and silly questions [but] they won't work," Peters, also Deputy Prime Minister, told reporters.

New Zealand First MP Tracey Martin said: "I don't know anything about it."

Cabinet minister Shane Jones, also a New Zealand First MP, said: "All korero on those matters are to be referred to our leader."

Peters said he looks after the "political wing" of the New Zealand First Party. He said the questions being raised related to "an administrative issue [so] you've got to ask somebody else".

But the foundation's trustee, Peters' lawyer and right hand man Brian Henry, had nothing to add.

"The party's dealing with it because there's an allegation that the party has done all sorts of naughty things and that's for the party to deal with, not me," he told Newshub.

National leader Simon Bridges said if what's been alleged is true, "you have the most significant electoral law breaches we've ever seen in New Zealand".

ACT leader David Seymour described it as "dodgy with a capital D".

The Electoral Commission told Newshub it had not been shown any of the documents referred to by Stuff. It said they'll be contacting New Zealand First and the foundation for further information.

Peters, when asked how intertwined the NZ First Party and NZ First Foundation are, referred back to a press statement which said he looked forward to speaking with the Electoral Commission.

In a statement Peters says the allegations "concern a party matter" and that he's "confident New Zealand First has operated within electoral laws".

Peters says "declarable donations were declared" and our "democracy is based on the secrecy of the ballot and privacy of party memberships and donations within specified limits".

Andrew Geddis, a Professor at the University of Otago's Faculty of Law, told Newshub: "For the party, it raises real questions as to why it is structuring its fundraising in a way that does not allow the public to see who its really big money donors are."

Peters has been down this road before. In 2008, he stood down as Foreign Minister while the Serious Fraud Office investigated donations to his party.

"There were three full scale inquiries; they all found us to be innocent of all those allegations and they will again now," Peters said on Tuesday.

During the 2008 scandal, then-National leader John Key ruled out working giving Peters a ministerial role in any National-led government.New Zealand First didn't make it back to Parliament that year.

The current National leader seems to be taking a cue.

"It doesn't make it more likely we will work with New Zealand First, that's for sure," Simon Bridges said.