Floodwaters are threatening to cut off Katikati, in the Bay of Plenty.
The township is now bracing for high tide in an hour.
State Highway 2 has already been closed to the north and heavy rain is causing major flooding on roads south of the township.
Police said on its Facebook page the heavy rain had caused flooding in low-lying areas.
Taiwan is on high alert ahead of the arrival of "near-perfect" super typhoon Nepartak, expected to slam into the island early on Friday morning local time.
The week is set for a wet finish - but there are some low temperatures and frosty conditions on the way again this weekend.
The low pressure system which brings rain to parts of the North Island won't produce too much for too long - but as it leaves, our temperatures will fall for the second weekend i
The rain arrives on Friday, in the form of a massive low pressure system covering the entire width of the Tasman Sea, stretching from southeastern Australia over to New Zealand.
A strong southeasterly airflow lies over the North Island as a result, while there's rain in many places - falling heavily at times.
A massive system of low pressure and rain is spread out across the Tasman Sea, bringing wet weather to Australia and New Zealand on Thursday night and into Friday.
There will be patches of heavy rain in parts of the country, while subtropical air will boost the rainfall levels - particularly in the North Island.
Power prices are an ongoing worry for many people, who hold back heating their homes in a bid to cut down on the power bill, a survey shows.
Figures from a new Consumer NZ survey showed 38 per cent of people said their homes were not as warm as they would like because they were restricting their energy use to keep bills down.
A foggy midweek quickly turns to a wet one, as Thursday and Friday see a front move in from the Tasman Sea, bringing rain and some strong winds.
The unsettled weather sticks around through to the weekend, before winds ease on Saturday and the rain dies away - but temperatures will stay low for the second weekend running.
A large frontal system finally arrives in New Zealand on Thursday, sweeping over the North Island first from the Tasman Sea.
Associated strong northeasterly winds develop over the upper North Island in the afternoon, becoming gusty by evening further south.
The large, rain bringing low pressure system is already causing problems across the Tasman Sea, with flood advisories in effect in the southeastern corner of Australia.
Rain is on the way for New Zealand too, starting on Thursday - as the system starts to track southwards after making landfall in the North Island.
Fog is again causing travel chaos at Auckland Airport.
Nearly 30 domestic flights have been cancelled, and 18 are delayed.
Four flights to and from Christchurch have been delayed because of the conditions.
The fog has not affected flights to Wellington, Dunedin and Queenstown.
International flights are also unaffected.