The Minister for Local Government has rejected the Napier City Council's request to have more time for considering Māori wards.
Councils had until 21 May to decide whether to have the wards in time for next year's local elections.
The Mayor, Kirsten Wise, argued the council did not have time to consult with the community on top of its other work.
In a letter to the minister, Nanaia Mahuta, Wise said mana whenua were strongly calling for the wards, and she asked for an extension.
But Mahuta wrote back, saying it was not possible.
That was because a change of deadline would require urgent law changes, and create uncertainty for other councils.
The Hawke's Bay Regional Council and the Hastings District Council unanimously agreed to establish Māori wards earlier this month.
RNZ
