MetService has issued a severe weather warning with heavy rain expected for the Bay of Plenty west of Tauranga and Coromandel Peninsula.

Heavy rain is forecast for the northern and eastern parts of the upper North Island, says a MetService spokesperson.

"A low to the west of the upper North Island directs a moist and unstable northeasterly flow over the area."

MetService advises that a Heavy Rain Warning remains in force for Northland, while Heavy Rain Watches are now in force for eastern parts of Auckland north of Orewa, Great Barrier Island, Coromandel Peninsula, and Bay of Plenty west of Tauranga.

People are advised to stay up to date with the latest forecasts in case any changes are made.

Heavy rain warning
Heavy rain may cause streams and rivers to rise rapidly. Surface flooding and slips are also possible and driving conditions may be hazardous.

Area: Northland
Valid: 16 hours from 8:00 am Monday to 12:00 am Tuesday
Forecast: Expect a further 70 to 100mm of rain to accumulate on top of what has already fallen, mainly in the north and east. Peak rates of 15 to 25mm/h, but 25 to 40mm/h possible in localised thundery downpours, especially in the north and east.

"Please note, showers are forecast after this time on Tuesday, with the possibility of localised thundery downpours, but widespread heavy rain is not expected to continue," says a MetService spokesperson.