Weather: Coromandel pummelled by rain as flooding, slips, debris impact roads

Northern regions of New Zealand were pounded by rain overnight, causing flooding, debris to be strewn across roads and slips to impact motorists.

Kiwis in parts of Northland and Coromandel witnessed a large downpour of rain on Wednesday night, and for some places, it keeps on coming. MetService has several rain and thunderstorm watches and warnings in place for the regions.

The New Zealand Transport Agency (NZTA) says the Kopu-Hikuai Rd on the Coromandel Peninsula is closed due to flooding.

Coromandel Civil Defence controller Garry Towler told Newshub there had been 200mm of rain recorded at the Pinnacles, which isn't unusual for a weather event like this, but it was still having an impact.

"The Kauaeranga river at Thames is running very high at the moment and it will be touch and go as to whether we have to close it or not at the 10am high tide so we will just keep an eye on that one," he said on Thursday morning.

Further south, he said a "deluge" of rain means that the Tairua River will likely flood at Hikuai at high tide. 

"Other impacted areas are between Kopu and Paeroa. There is lots of flooding there. The highway is open to one-lane at present and roading contractors have staff there monitoring that."

While Towler said the worst of the weather seems to have passed, authorities would keep an eye on catchments and a team would assess conditions at daylight. He had already been notified of some slips, however.

"We are just advising everybody, if they are planning on travelling on the Coromandel or through the Hauraki, just to take care and check road conditions before they come. There is a lot of debris and small slips everywhere which is usual for this kind of event."

"The northern Coromandel, they got away with it this time. The impact of the weather event was certainly on the eastern seaboard, down Pauanui, Tairua, Whangamata area."

MetService on Thursday morning issued a severe thunderstorm watch for Auckland, Coromandel and Bay of Plenty.

"A front is expected to move slowly southwards over southern Auckland, Coromandel Peninsula and western Bay of Plenty this morning. There is a moderate risk of thunderstorms associated with this front, some of these may be severe bringing localised downpours of 25 to 40mm per hour.

"Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips."

It also bucketed down in Auckland overnight and on Thursday morning. Currently, the only major impact appears to be surface flooding on the southern motorway heading north.

"Due to surface flooding near the Orams Rd overbridge, after Hill Rd on-ramp, AklTraffic is moving very slowly in the area with delays currently from Takanini and growing. Delay your journey or consider alternative route," NZTA says.

Auckland Transport is calling for people to take extra care.

"There are patches of surface flooding on many roads around Auckland this morning. Please stay alert, keep your lights on, increase following distances and allow extra time for your morning commute today."