MetService has lifted its severe thunderstorm warnings for the Bay of Plenty region.

It said, "localised downpours of 2-40mm/h are still possible".

MetService has issued a severe thunderstorm warning for Waitomo, Taupo, Ruapehu and Otorohanga.

Severe thunderstorms were detected near Benneydale, Waipa Valley and Mangapehi at 8.37pm, MetService said.

"These severe thunderstorms are moving towards the southsoutheast, and are expected to lie near the Hauhungaroa Range at 9.07pm and near Turangi, the Hauhungaroa Range, Lake Taupo, and Kuratau Junction at 9.37pm."

These thunderstorms are expected to be accompanied by very heavy rain, MetService said.

MetService meteorologist Katie Lyons said the Wellington region, which was hit hardest by torrential rain today, is expected to get some slight relief tomorrow, allowing clean-up efforts to continue.

The Tararua Range, Kāpiti Coast and Wellington remain under an orange heavy rain warning until 1am tomorrow.

“That’s really just to cover the tail end of the rain that’s over the region at the moment,” Lyons said. 

“The system that brought flooding this morning was a frontal band with embedded thunderstorms. While that has moved off, there’s still a background of benign rain.”

She said that although the worst of the rainfall has passed, some areas remain “particularly sensitive” following this morning’s severe downpours.

Lyons said tomorrow will not be completely dry for the region, but there will be moments of relief.

“For a lot of people affected today, it’s not as though they’ll be able to easily get out tomorrow and clean everything up all at once,” she said. “But there should be some periods where they can do that.”

A steady rain is falling in Lower Hutt this evening, and officials are bracing for heavier downpours tonight.

The city is calm compared to the scenes of silt-soaked streets in Stokes Valley earlier today, following early morning rain that sent water and mud flowing through the suburb.

But the rain has been getting heavier as the night has gone on, and is now falling quickly.

With an orange heavy rain warning in place until 1am, Lower Hutt deputy mayor Keri Brown says the city isn't clear of danger yet:

"It's been a very intense and stressful time, particularly in Stokes Valley, but you would have seen, the community really mobilised," she says.

"[The city] is not out of the woods yet, the predictions are we could have another band of intense rain until 8pm - possibly later, because we can never do it down to a fine detail."

– RNZ

Several northern and central regions of the North Island remain under a severe weather watch through tomorrow.

MetService's latest heavy rain watches are below:

Area: Northern and eastern parts of Northland north of Whangarei
Period: 8 hours from 9pm tonight to 5am tomorrow
Forecast: Periods of heavy rain with possible thunderstorms, and a low risk of localised downpours. Rainfall amounts may approach warning criteria in localised areas.
Moderate chance of upgrading to a warning.

Area: Auckland south and west of Warkworth
Period: 19 hours from 1am to 8pm tomorrow
Forecast: Periods of heavy rain, with thunderstorms possible and a low risk of localised downpours. Rainfall amounts may approach warning criteria, with a front early morning and then a trough late afternoon or early evening.
Moderate chance of upgrading to a warning.

Area: Waikato, and the remaining parts of Taupo and Bay of Plenty not already covered by a warning
Period: 12 hours from 9pm tonight to 9am tomorrow
Forecast: A period of heavy rain, with possible thunderstorms and a low risk of localised downpours, amounts may approach warning criteria in localised areas.
Moderate chance of upgrading to a warning.

Area: Gisborne north of Tokomaru Bay
Period: 14 hours from 6am to 8pm tomorrow
Forecast: Periods of heavy rain, with thunderstorms possible. Rainfall amounts may approach warning criteria.
Moderate chance of upgrading to a warning.

Part of State Highway 43 Forgotten World Highway is closed due to flooding and slips.

NZTA said heavy rainfall caused "a number" of slips between Whangamōmona and Taumarunui, closing that stretch of road overnight. 

"Stratford to Whangamōmona remains open, however, with more rainfall predicted overnight, please drive to the conditions and take care."

SH3 between Mokau and Piopio is also closed overnight.

"Both state highways will remain closed until crews can assess the roads tomorrow morning for any possible damage," NZTA said.

NZTA says State Highway 2 Waioweka Gorge is closed due to expected heavy rain.

"With the ground still unstable and the Goldsmith Slip not yet fully cleared, keeping the Gorge closed is the safest option," NZTA said.

The Bay of Plenty east of Whakatāne River is under an orange heavy rain warning from 3am to 4pm tomorrow.

The road will be closed until the weather has passed and it has been inspected. This is expected to be tomorrow evening.