"Council did something that was untenable by changing the zoning without telling anybody from nearly 30,000 households," he said.
The vote means the council will withdraw "out of scope" changes -- which residents did not ask for in the proposed plan, and there is no formal right of reply.
The decision is Mayor Len Brown's biggest defeat in six years and a blow for Deputy Mayor Penny Hulse, the political face of the Unitary Plan since 2013. It has created uncertainty for the plan, the rulebook for shaping the future of the city.
Mr Brown was confident the plan would be completed by the August deadline. Ms Hulse said the council would need to review the legal situation.
Legal advice to councillors at the meeting said "withdrawal of the council's evidence ... would result in significant detrimental legal and practical consequences to the council and its community".
Mr Brown said the council would no longer have a role in the hearings process on residential zoning. The panel would hear all other submissions and deliver recommendations to the council in July.
Mr Brown denied the council leadership had botched the process, saying it had gone through three levels of consultation with the community.
At the end of the meeting, Ms Hulse said a bit of leadership was needed.
"We need to start with a slightly more truthful set of information from the community, ourselves and all the players in this," she said.
The proposed changes, first reported by the Herald in December, caused a public uproar. About 660 people attended a public meeting on the issue in Kohimarama this month.
Youth groups such as Generation Zero and the council's youth advisory panel urged councillors to stick with the proposed changes.
Said Generation Zero spokesman Dr Sudhvir Singh: "We cannot allow any further delays to the implementation of this plan as Auckland urgently needs more housing supply, particularly ... close to public transport and town centres."
How they voted
To withdraw the changes
• Cameron Brewer
• Cathy Casey
• Ross Clow
• Chris Darby
• Chris Fletcher
• Denise Krum
• Mike Lee
• Dick Quax
• Sharon Stewart
• John Walker
• Wayne Walker
• John Watson
• George Wood
To keep the changes
• Mayor Len Brown
• Deputy mayor Penny Hulse
• Arthur Anae
• Bill Cashmore
• Linda Cooper
• Alf Filipaina
• Calum Penrose