Auckland Council is refusing to reveal details about mayor Len Brown's new office - because the information could put the mayoral chains at risk.
The mayor's staff have largely rejected a Local Government Official Information and Meetings' Act request from the Herald on Sunday for correspondence about his new office, which contains a private bathroom and dressing room hidden behind a bookcase.
The space - which mayoral office staff said was designed without the mayor's input - raised eyebrows among Brown critics in December because of his extramarital affair with former council advisory board member Bevan Chuang.
The pair had sex in the mayoral office and other council rooms during their two-year affair.
On December 10, the Herald on Sunday asked the mayor's office for all correspondence about the new office.
The 10-page response was heavily censored. Official information adviser Nicole Miell wrote that some information was withheld because it was not within the scope of the request.
Other parts were blacked out because, under the act, they could "prejudice the maintenance of the law". This included the prevention, investigation and detection of offences and the right to a fair trial, she wrote.
The Herald on Sunday asked mayoral office spokeswoman Melanya Burrows how the information could prejudice the maintenance of the law.
The information was blacked out for security reasons, she said. "The correspondence details the storage of the mayoral chains."
The collection of chains included those from legacy councils, were made of various materials and ranged in value.
She said there were seven chains but did not know what each was worth. "To our knowledge, no one has threatened to steal them nor have they ever been stolen before."
They were locked in a safe when the mayor was based in the Town Hall. Brown, councillors and more than 2000 staff moved to the former ASB Tower last year.
Canterbury University law professor Ursula Cheer, a specialist in media law, described the council's response as "rather odd".
"It seems quite an unusual use of that particular ground in the legislation.
"Burglars are going to assume they're there somewhere anyway ... you'd think [prejudice of the maintenance of law] would be something to do with perhaps the operation of the police, or perhaps the security services. Sort of bigger stuff, more sort of national stuff, rather than just fear of individual items being stolen."
Councillor Christine Fletcher said the chains used by Brown were those worn by her when she was Auckland City Council mayor.
They were solid gold.
"I don't know the ins and outs of what you've just described to me ... but I would like to think the security of those chains is paramount.
"They are precious and part of the heritage and history of Auckland."
Invercargill mayor Tim Shadbolt famously lost the mayoral chains when he led Waitemata City Council in the 1980s.
Those chains were made of tin with a gold coat and were worth just $3,000, whereas the chains he now used were made of "pure gold from Queenstown" and insured for $250,000.
Shadbolt said the grounds for refusing the information were unusual.