The allegation that Mayor Len Brown had sex with his mistress in Auckland Town Hall's Ngati Whatua room has surprised the iwi.

A signed affidavit outlining the alleged incident was posted online yesterday.

The author's name was blacked out, but she has been widely identified as Bevan Chuang.

It alleges the two were "sprung" by a security guard while having sex in the room early last year. The guard apologised and left, Ms Chuang said.


"Mr Brown was also quite distressed, stating, 'This is it, this is it'."

Ngati Whatua o Orakei spokesman Ngarimu Blair said the Ngati Whatua room had symbolised the iwi's relationship with the Auckland City Council since it was established in 1998. He said the room, which was frequented by dignitaries and council staff, was noa, meaning it was not tapu or sacred and not used for ritual or ceremonial purposes.

"But it's fair to say we didn't envisage that it would be used in this way," he said. "It's a pretty dramatic way for people to learn that we have a Ngati Whatua suite."

Asked what his people's reaction would be to Mr Brown's encounters, Mr Blair remained diplomatic.

"We will just leave the mayor the space and time to do what they have to do," he said.

"We will meet the mayor, who has expressed a desire to continue in due course and we will talk kanohi ki te kanohi [face to face]."