Auckland City Mayor John Banks has pulled out of the first head-to-head debate with his main rival for the Super City mayoralty, Manukau Mayor Len Brown.

Between 50 and 60 people had booked tickets to a Trans Tasman Business Circle lunch on March 23 to hear the two heavyweight guests.

When Mr Banks learned he was sharing the stage with Mr Brown, he contacted the organisers and pulled out. The event was subsequently cancelled.

Events manager Sharron Lloyd sent an email to guests blaming "unforeseen circumstances" and telling them they would receive a refund.

Mr Banks yesterday said he was not sharing a joint platform with any of the candidates until the last 90 days of the campaign.

"We are running our own campaign as other candidates are running theirs," he said.

Mr Banks said his office agreed to the event, but his campaign team was saying no to all joint invitations.

He said he was looking forward to fronting up to Mr Brown and other candidates in the last 90 days.

Mr Banks also refused to appear on Morning Report with Mr Brown yesterday.