Auckland Mayor Phil Goff has come out swinging amid a potential Serious Fraud office probe into his campaign finances, maintaining he has "nothing to hide".
The SFO in a statement released earlier this month confirmed receipt of a referral from police in relation to Goff's election expenses.
The SFO is yet to confirm a formal investigation.
Goff, meanwhile, says he is not worried about the police referral.
"I've got nothing to hide. We've kept, to the best of our knowledge, within all of the rules," Goff said.
"The SFO haven't contacted me - I've got no idea what it's about."
A spokesman for the SFO would not be drawn when asked whether Goff, or his office, had been contacted.
They would not say whether the complaint related to Goff's expenses during his 2016 or 2019 mayoral campaign, or both.
Goff understood the SFO was still mulling whether to launch an investigation.
"If they do decide to do that I will front up to them," he said.
Staffers working on his national and local government campaigns were under strict instructions to "stay within the law", Goff said.
"[The SFO] should just get on and do their job and I'll cooperate fully with them in that," he added.
"I'm not anxious about it.
"I think we've done exactly what we should've done."
Last September, electoral officer Dale Ofsoske passed a complaint about Goff's 2016 election expenses to police.
A $366,000 auction declaration did not specify individual donations or purchases, which included the sale at an auction of a book for $150,000.
The book had belonged to Goff, a former minister of foreign affairs, and had been signed by Chinese President Xi Jinping.
Police made "a number of inquiries" but the timeframe for a possible prosecution expired in December.
At the time, Ofsoske said the complaint was under section 112D of the Local Electoral Act 2001 - 'Filing a false return of electoral donations and expenses'.