Heavy rain hammers New Zealand

Emergency services are bracing themselves with torrential rain hammering the country overnight and rising tides this morning threatening to cause more damage.

Wellington Police are this morning urging residents to keep away from waterfront areas, such as Greys Rd north of Porirua, with the inlet highway around Pauatahanui expected to be submerged as high tide arrives around 7am.

Constable Rob Taylor said Porirua police responded to numerous flood callouts last night, which included phone calls from residents saying there was "water lapping at their back door".

“With the amount of water the in-coming tide, that will put the [waterfront roads] under."

The heavy rain had caused drains to overflow and flood roads cross the city. “We’ve had major intersections going completely under water.”

Police evacuated residents from houses in Court Rd, Tawa, a police spokesman said.

Parts of Titahi Bay were facing a possible evacuation last night, but this had been called off around midnight though emergency services were keeping a watching brief overnight, he said.

One woman had to be rescued by ambulance staff after her vehicle became submerged in a flooded Porirua street. The woman was unharmed, but the car was "well under water", Mr Taylor said.

Heavy rain tonight just north of Wellington should ease in the morning, the Metservice said.

Meanwhile, Civil Defence has asked residents in North Otago to avoid driving as heavy rain has virtually isolated Oamaru.

There have been multiple road closures and people have been asked to stay alert with more rain predicted late tonight.

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This particularly applied at Kakanui, south of Oamaru, with up to 300mm of rain expected to fall in the Kakanui-Dasher catchment overnight.

The Kakanui Bridge which links one side of the township, 14km south of Oamaru, to the other was closed at 7pm tonight.

Waitaki Civil Defence spokesman Rowan Carroll said the Kakanui River was continuing to rise and was flowing at 956 cubic metres a second at 9pm. It breached its banks at several points today.

"The Kakanui Hall has been put on standby as an assembly point for evacuees," she said.

However, in the meantime Civil Defence was asking people to stay put and avoid travelling unless absolutely necessary.

All residents were asked to listen to local radio for further updates and those on rural water supplies were advised to conserve water.

The Kakanui river mouth had re-opened and it was hoped this would ease the situation as water levels in the lagoon had dropped. However, further rain was expected.

The Shag River was being monitored, with high tide due at 1am.

Motorists were asked not to travel unless absolutely necessary and to take extreme care.

State Highway 1 north of Oamaru was closed at Waitaki Bridge and at the SH83 junction, with no detours available. Its intersection with SH82 was closed, and SH82 and SH83 were also closed. South of Oamaru, State Highway 1 was closed at Maheno, open at Hampden, but closed at Palmerston and Cherry Farm.

A property in York Street in Oamaru was evacuated earlier today as was the Oamaru Camping Ground, and workers at Pukeuri's Alliance meat works were sent home at 10am.

In Canterbury forecast coastal swells of up to four metres could block off river mouths and flood land.

Environment Canterbury's Timaru-based flood controller Malcolm Miller said the swell was most likely to cause problems at high tide, around 1am, with the area from the Waitaki River to the north of Timaru most likely to be affected.

Periods of heavy rain were expected in the area through to tomorrow afternoon with a further 80-120mm of rain expected about the hills and ranges, and 30-50mm in low-lying areas.

Some foothills rivers had risen sharply this afternoon, including the Waihao River at McCulloughs Bridge.

In Otago, the Otago Regional Council warned of potential flooding in the Taieri catchment. The Water Of Leith in central Dunedin was running very high, but was not expected to spill its banks.

The eastern Bay of Plenty was in for a dose of heavy rain tonight, with most of it set to fall east of Opotiki, the MetService said.

Rain has caused slips on road in the region and one Whakatane house was evacuated today. The rain is expected to ease tomorrow morning and is expected to remain below warning thresholds.

The MetService also warned tonight of possible gales about Banks Peninsula, Westland and Fiordland.

Gales were also expected over northern New Zealand, with gusts above 110kmh possible in northern Waikato.