A subtropical low is bringing heavy rain and severe gale northeasterlies to parts of New Zealand says MetService which issued a severe weather warning on Wednesday evening.

"A subtropical low over the Tasman Sea directs a strong and moist northeast flow over New Zealand, with some areas likely to receive warning amounts of rain and possible severe gale northeasterlies," says a MetService spokesperson.

"Also note that large northeast swells could bring hazardous conditions to exposed coasts."

Heavy rain could cause slips, surface flooding and damage to roads. Severe gales could make driving conditions hazardous, especially for motorcycles and high sided vehicles. Trees may be toppled and power lines damaged. Temporary structures such as tents could be affected.

People are advised to keep up to date with the latest forecasts from MetService in case any changes are made, or further areas are added.

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: 9 hours from 9:00pm Wed 4 Jan to 6:00am Thu 5 Jan
Forecast: In addition to the 70 to 100 mm that have already accumulated expect a further 60 to 80 mm south of the Bay of Islands. Peak rates of 10 to 25 mm/h.

Area: Coromandel Peninsula
Valid: 26 hours from 9:00pm Wed 4 Jan to 11:00pm Thu 5 Jan
Forecast: In addition to the 50 to 70 mm that have already accumulated expect a further 140 to 180 mm. Peak rates of 10 to 20 mm/h.

Area: Bay of Plenty west of Matata
Valid: 36 hours from 9:00pm Wed 4 Jan to 9:00am Fri 6 Jan
Forecast: Expect 140 to 200 mm of rain to accumulate. Peak rates of 10 to 20 mm/h expected. Note that this warning may be extended since further bursts of heavy rain are possible during the remainder of Friday and into Saturday.

Area: Tasman northwest of Motueka
Valid: 36 hours from 11:00pm Wed 4 Jan to 11:00am Fri 6 Jan
Forecast: Expect 200 to 250 mm of rain. Peak rates of 15 to 25 mm/h expected Thursday evening and overnight Thursday.

Area: The ranges of Westland south of Otira
Valid: 24 hours from 4:00am Thu 5 Jan to 4:00am Fri 6 Jan
Forecast: Expect 120 to 150 mm of rain. Peak rates of 10 to 20 mm/h expected.

Strong Wind Warning:
Strong wind gusts could damage trees, powerlines and unsecured structures. Driving may be hazardous, especially for high-sided vehicles and motorcycles.

Area: Auckland including Great Barrier Island
Valid: 8 hours from 9:00pm Wed 4 Jan to 5:00am Thu 5 Jan
Forecast: Severe gale northeasterlies gusting 110 km/h in exposed places.

Heavy Rain Watch:
Area: Auckland including Great Barrier Island
Valid: 12 hours from 9:00pm Wed 4 Jan to 9:00am Thu 5 Jan
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria, especially in the north and east.

Area: Mount Taranaki
Valid: 43 hours from 1:00am Thu 5 Jan to 8:00pm Fri 6 Jan
Forecast: Periods of heavy rain. Rainfall amounts may reach warning criteria.

Area: The Richmond and Bryant ranges including the Rai Valley, also the Marlborough Sounds
Valid: 30 hours from 3:00am Thu 5 Jan to 9:00am Fri 6 Jan
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Strong Wind Watch:
Area: Northland
Valid: 3 hours from 9:00pm Wed 4 Jan to 12:00am Thu 5 Jan
Forecast: Northeast winds may approach severe gale in exposed places.

Area: Waikato, Coromandel and western Bay of Plenty to Taranaki and Taihape
Valid: 18 hours from 9:00pm Wed 4 Jan to 3:00pm Thu 5 Jan
Forecast: Northeast winds may approach severe gale in exposed places.

Watches no longer in Force
Strong Wind Watch lifted for Banks Peninsula: Severe gales are no longer considered likely and the watch is lifted.