MetService said the area could get up to 140mm of rain.
“Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.”
Heavy rain watches are in place for Northland, Auckland - north of Takapuna - and Great Barrier Island from tomorrow evening.
Strong wind watches are also in place for Northland - south of the Bay of Islands - and for Auckland north of the Harbour Bridge, Great Barrier Island and Coromandel Peninsula.
MetService warned that gales could be severe.
Further south, a heavy rain watch has been issued for Bay of Plenty, including Rotorua, from 9am on Friday to 3am on Saturday and for the ranges of Hawke’s Bay north of Hastings from midday tomorrow to midday on Friday.
It will also be windy in the Bay of Plenty and Taupo with watches issued for areas east of Whakatane and east of Lake Taupo from midday tomorrow through to midday Friday.
MetService said swells on the eastern coasts of the island could reach up to 5m.
“This, in addition to the heavy rain forecast, will make these coasts vulnerable to damage so be prepared and keep safe.”