Len Brown is a mayor under stress, say colleagues, but the man himself insists a self-inflicted chest and head beating on Tuesday night was nothing more than a Maori gesture.

During a speech in which he apologised to Manukau City councillors for credit card breaches, Mr Brown said that last Friday morning he went down to Howick and sat on the main street. Then just stood there.

In his speech, Mr Brown beat his chest repeatedly and hit his face with an open hand as he said, "Got a problem? You come see me. Here."

Mr Brown declined to comment on his state of mind, but his mayoral campaign spokesman David Lewis said he was back on an even keel yesterday after a "highly stressful day" on Tuesday.

Mr Lewis said Mr Brown was a more emotional person "than you and I" and a 20-minute speech to the policy and activities committee was a case of wearing his heart on his sleeve. He said the chest and head beating was a Maori gesture, kanohi te kanohi, inviting people to tackle him face-to-face.

It was the most emotional moment of an impassioned speech in which the first-term Mayor apologised for errors and mistakes, spoke of the thrashing he had given himself and asked for a fair hearing from the Auditor-General, not a kangaroo court.

"Either you give me a break and let me have the opportunity of a fair hearing to get some justice, equity and fairness, or sink into a cesspit of political expedience. I'll leave it up to you."

Referring to his near-death heart attack in 2008, Mr Brown said: "Do you think I got off that bloody bed and came back here because I was worried I could spend some more money on the credit card?

"You know why I came back here. You saw me when I walked back into this place, I was a bloody skeleton. I came back here for the love of the people and you know that's damn right."

Yesterday, political commentators were divided on the damage to Mr Brown's Super City mayoral chances from the political and media scrutiny during the past fortnight over revelations he used his council credit card to make personal purchases and failed to properly account for the spending.

Councillor Colleen Brown, who was in the chair for Tuesday's "nasty and vindictive tone in the chamber", said the scrutiny was a low point for Mr Brown's mayoralty but praised him for a gutsy performance. She denied reports Mr Brown broke down in tears.

Even Jami-Lee Ross, the Citizens & Ratepayers Super City candidate leading the attack on Mr Brown, accepted the apology, saying it was time to leave matters to the Auditor-General.

Mr Ross denied going overboard with his attacks on Mr Brown, saying he was doing the job of holding the Mayor to account.

Left-wing political commentator Chris Trotter said Mr Brown's emotional speech had gone a long way to "lancing the boil", it showed contrition and it would stand him in good stead with voters.

Right-wing commentator Matthew Hooton took the opposite view, saying Mr Brown was toast and had no chance of leading the Super City.

David Wilson, director of the Institute of Public Policy at Auckland University of Technology, said Mr Brown had been damaged in the short term but could recover relatively quickly.