Heavy rain forecast to batter Auckland overnight may cause headaches for commuters about the region tomorrow morning.

MetService meteorologist Nick Zachar said a wave of heavy rain was due to move south-southeast over Northland and Auckland this evening.

READ MORE: Auckland braces for severe rain

In Auckland, the rain would get worse throughout the night, with heavy rain predicted to be "just short of flood levels".

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"Looks like there will also be more heavy rain in the morning, but it will be done before dawn or so -- so before about 6am or 7am, it should be out of the area and into the east."

WeatherWatch head analyst Philip Duncan urged motorists in the Auckland region to leave 15 to 20 minutes earlier tomorrow morning due to the forecast heavy rain.

Motorists were also warned to watch for pockets of surface flooding on Auckland streets, highways and motorways, he said.

There was also a chance of some surface flooding for those in low lying areas.

"For most parts of Auckland it will just be more steady rain with some heavier falls."

Auckland Civil Defence has also warned short bursts of severe weather would coincide with a near king tide tonight in Auckland.

It said strong northerly winds were expected to build from 9pm, which could cause waves and possible flooding of some low-lying coastal roads between 10.30pm and 12.30am.

In particular, low-lying parts of Tamaki Drive, west of the Ngapipi Rd intersection, were expected to be affected by waves and flooding, Civil Defence said.

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It was also possible waves might breach the top of the Tamaki Dr seawall in places, and transport agencies and police would monitor the situation, and close parts of Tamaki Dr if necessary.

Civil Defence also warned motorists that surface flooding could make driving difficult, and encouraged those on the road to drive to the conditions.

Severe weather warnings are also in place for Northland, Mt Taranaki and the eastern Bay of Plenty ranges tonight.

Mr Zachar said heavy rain was beginning to hit areas around Mt Taranaki, and would continue to move eastwards into tomorrow morning.

"Most of the rain will be out out of the area by mid morning."

Once the rain cleared it was looking like a fine and sunny day for most of the North Island tomorrow, Mr Zachar said.

It was also fine further south, however, a cold front moving up the country would reach the upper South Island by the end of tomorrow.

"That will bring a short burst of shower activity, it won't be too many showers, but it will mean at least a chance of rain.

"Behind that front into the weekend, there will be southwesterlies and cooler conditions. So we are expecting a drop in temperature during the first part of the weekend for both islands.

"It will be chilly and showery, so not a lot of widespread rain but there will be shower activity especially about the coast."

Tomorrow's forecast:

Auckland

- Early rain, chance heavy, then fine. Light winds. High 16C, low 10C

Wellington

- Early rain then fine spells. Southerly turns to strong northerly. High 12C, low 8C

Christchurch

- Mainly fine, evening high cloud. Northerlies. High 13C, low 1C

Friday's forecast:

Auckland

- Showers. Rain overnight, chance heavy. Fresh westerly. High 14C, low 7C

Wellington

- Early rain, then a few showers. Strong northwest. High 12C, low 4C

Christchurch

- Morning rain, then high cloud. Southwesterly turns northwesterly for a time. High 10C, low -1C

(Source: MetService)