A fire at a Kāinga Ora apartment block in Auckland, which left dozens of flats without power and water, is now being treated as suspicious.

The fire at the complex in Ōtāhuhustarted in the early hours of Sunday.

Six tenants had to be evacuated from the three-storey building, within a residential complex on Albert St. And as a result of the fire, 56 flats lost power and water.

Police said the fire was being treated as suspicious and the cause was under investigation.

Kāinga Ora earlier said no one was injured and it had arranged alternative accommodation for the people who were displaced.

It was still assessing the extent of damage to the building.

The agency had not yet confirmed whether power and water had been restored to all the flats.