Heavy rain is continuing to be forecast for parts of the North Island, along with the west of the South Island.

A heavy rain warning and watch remains in place for the Bay of Plenty, from Rotorua to Te Kaha.

In an updated statement today, the MetService says a moist north to northeasterly aistream will bring outbreaks of heavy rain to New Zealand this week.

"Warnings and Watches are in force for many areas, and more are likely to be issued during the coming days.

"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 Warning - Orange.

Area: Bay of Plenty east of Te Kaha and Gisborne north of Tokomaru Bay
Valid: 26 hours from 9am Tue 2 May to 11am Wed 3 May
Forecast: Expect a further 120 to 150 mm of rain, in addition to what has already fallen, mainly about the ranges. Peak rates of 15 to 25 mm/h.

Area: Tasman northwest of Motueka
Valid: 11 hours from 9am Tue 2 May to 8pm Tue 2 May
Forecast: Expect a further 40 to 60 mm of rain, in a addition to what has already fallen, mainly in the ranges. Peak rates of 10 to 20 mm/h.
Please note that further periods of heavy rain are forecast later on Wednesday and during Thursday, and this warning is likely to be extended closer to that time.

Area: Westland south of Otira
Valid: 45 hours from 9am Tue 2 May to 6am Thu 4 May
Forecast: Expect 300 to 450 mm of rain in the ranges, and 100 to 150 mm nearer the coast. Peak rates of 15 to 25 mm/h in the ranges, but possibly up to 35 mm/h Tuesday afternoon and again from Wednesday morning with thunderstorms possible.

Area: Fiordland north of Doubtful Sound
Valid: 35 hours from 11am Tue 2 May to 10pm Wed 3 May
Forecast: Expect 200 to 300 mm of rain. Peak rates of 20 to 30 mm/h expected Tuesday afternoon, and again Wednesday morning and afternoon, with thunderstorms possible.

Heavy Rain Watch
Area: Northland
Valid: 55 hours from 6am Wed 3 May to 1pm Fri 5 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Bay of Plenty from Rotorua to Te Kaha
Valid: 30 hours from 9am Tue 2 May to 3pm Wed 3 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Tongariro National Park
Valid: 24 hours from 3am Wed 3 May to 3am Thu 4 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.

Area: Taranaki, about and north of the Mountain.
Valid: 48 hours from 2pm Wed 3 May to 2pm Fri 5 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria, especially about the Mountain.

Area: Buller south of Karamea
Valid: 66 hours from 9am Tue 2 May to 3am Fri 5 May
Forecast: Periods of heavy rain. Rainfall amounts may approach warning criteria.
Please note that rain is forecast to ease this evening, then reintensify Wednesday morning. This Watch has been extended.

Strong Wind Watch
Area: Westland south of Fox Glacier, and Fiordland north of George Sound
Valid: 5 hours from 9am Tue 2 May to 2pm Tue 2 May
Forecast: North to northeast winds may approach severe gale in exposed places.