Many parts of the country are set for a hosing in the coming days as a deep low crosses the Tasman Sea, with the heaviest falls expected to affect northern parts of the South Island.
Metservice is warning this could be a significant rain event for Nelson and Tasman and said there was a chance warnings in the area could be upgraded to red.
It has issued orange heavy rain warnings for the Tasman, Marlborough, Buller and Westland districts, along with Mt Taranaki in the North Island.
The deep low was forecast to direct moist northerlies over the country on Thursday and Friday, bringing with it heavy rain for northern and western parts of both islands, and northerly gales for parts of central New Zealand.
The Tasman District looks set to bear the worst of the rain, and with 350 to 450 millimetres of rain forecast, possibly more about the ranges and 150 to 250 mm elsewhere.
Peak rates of 25 to 35 mm/h expected about the ranges from late Thursday morning.
The orange heavy rain warning would be in place from 3am Thursday to 10am Friday and Metservice warned there was a moderate chance it would be upgraded to a red warning.
Heavy rain is also forecast in parts of Marlborough, with up to 300 millimetres of rain predicted to fall about the Richmond and Bryant ranges, at peak rates of between 20 to 30 mm/h and 100 to 150 mm elsewhere between 11am Thursday and midday Friday.
There was a small chance it could be upgraded to a red warning.
Orange heavy rain warnings were also in place for the Buller District, where 150 to 200mm of rain was expected, possibly 250mm about the Paparoa Range between Thursday afternoon and Friday morning.
The ranges of the Westland District, where were in line for 150 to 200mm of rain, possibly 250mm about isolated peaks, with the chance of thunderstorms.
Heavy rain watches were in place for other parts of the Nelson, Tasman, Grey and Westland Districts.
In the North Island, an orange heavy rain warning was in place for Mt Taranaki, where 150 to 250mm of rain was expected between midday Thursday and 4pm Friday.
A strong wind watch was in place for South Taranaki, Taihape and Whanganui, while heavy rain watches were in place for north Taranaki, Waikato, the Coromandel Peninsula, Auckland, Great Barrier Island and Northland.
For many of the regions it would be the most significant rain seen this year with parts of the country impacted by recent drought conditions.
