The Electoral Commission is looking into a complaint about the New Zealand Public Party's (NZPP) use of donations.

A spokesperson for the commission said the complaint was first sent to the Serious Fraud Office (SFO).

"The SFO has passed on a complaint to us about the collection and use of donations by the NZ Public Party," they said. "We are currently considering the complaint."

On Tuesday, NZ Public Party leader Billy Te Kahika said the internal financial party documents that prompted the complaint came from a person that has since left the party and they have had to correspond with them "via legal letters".

"The document that is an incomplete first draft of koha payments is being shared around. The document is now out of date and was only held by three people in our party: the person in question, Michael Stace (NZPP Party Director), and myself, Billy Te Kahika," he said.

"The kaupapa of our party is that we bring to light in the most transparent way possible any threats to our movement."

Te Kahika on Tuesday released financial documents, along with two legal letters the party sent to the person who has since left the party. He said the only redactions are to "protect the privacy of individuals".

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"To avoid any doubt, at all times we have acted within the law, we have acted with integrity, and we have acted transparently."

There are five documents, of which two are legal letters, that were released.

The first outlines koha given to the party at events throughout New Zealand during July and August, as well as events, travelling costs and cash payments made using donations. 

The second shows bank transactions relating to campaign expenses and the third is the trust deed between NZPP and Rubicon Crossing Ltd.

The two legal letters sent to the former party member say they made "defamatory statements" to party members while on Zoom calls. 

The second legal letter asks the former party member to pay $1000 in relation to a final contractor payment, and that all party documentation and information they've received is returned.

Te Kahika is standing in the Te Tai Tokerau electorate in the upcoming election.

He joined forces with former National Party MP and now Advance NZ leader Jami-Lee Ross earlier in the year.