Key Points:

The relationship between the media and New Zealand First leader Winston Peters has hit a new low.

Mr Peters walked out on a stand-up interview with journalists at Parliament this afternoon.

Reporters were seeking his response to a request from Act leader Rodney Hide for the Serious Fraud Office to investigate him.

But Mr Peters was not happy with the way journalists were standing near him.

When they refused to move from a lower step, he abruptly walked away refusing to answer any questions.

Mr Hide said questions raised by the media, including the Herald, about donations to Mr Peters' New Zealand First Party were issues of "high public importance" which required investigation.

Mr Hide said he had hoped Prime Minister Helen Clark would stand Mr Peters down from his Foreign Affairs Minister role and launch an investigation and was disappointed she had accepted his word that nothing illegal took place.

SFO director Grant Liddell confirmed he had received Mr Hide's complaint about the donations.

"Before I can commence an investigation using statutory powers under the Serious Fraud Office Act, I need to be satisfied that I have reason to suspect that an investigation may disclose serious or complex fraud," he said in a statement.

He said the office would assess the complaint and decide if an investigation was warranted.

The assessment process would start immediately but could take several weeks.

"The process involves considering the complaint and relevant available documentary or other material," he said.

"The complaint involves a matter of legitimate public interest which warrants prompt consideration."

Mr Peters' has refused to give detailed answers to questions over a $100,000 donation from Owen Glenn, donations from the Vela family and a $25,000 cheque from Sir Robert Jones to the Spencer Trust, run by Mr Peters' brother.

Speaking to Grey Power in Wellington this afternoon, he repeated his denial of any wrongdoing in the affair.

He said: "Make no mistake, this is a politically motivated smear campaign, built on unsubstantiated claims, innuendo and misinformation."

Mr Peters has said he will explain in Parliament today how there is a "massive difference" in his party funnelling large corporate donations through secret trusts and others doing the same thing.

Helen Clark said after a meeting with Mr Peters yesterday she accepted his assurances that nothing illegal had been uncovered by allegations swirling around her Foreign Minister.

Mr Hide said in a statement today: "It is my considered opinion that issues raised by the Dominion Post and the New Zealand Herald require proper and independent investigation.

"The Serious Fraud office is the appropriate Government department capable of carrying out an independent, thorough and competent investigation more so with its current powers.

"It is vital that such an investigation be seen to be unfettered by any suggestion of political interference, real or imagined."