Heavy rain is falling across the Western Bay and Bay of Plenty as a rain band moves south down over the country.
A severe weather warning is in place for Auckland, Coromandel Peninsula, Bay of Plenty, about the west of Te Puke, and the Kaimai Range, MetService says.
A MetService forecaster said people can expect more heavy rain as the evening progresses.
"This amount of rainfall could cause slips and surface flooding, as well as making driving hazardous, so people need to be aware of the risk and drive to the conditions."
More than 4000 properties in the Matua area were without power for about two hours this afternoon, while the power is still out at 37 properties in Whakamarama.
Powerco estimated it would be back on about 8pm.