It'll pay to make the most of the last few hours of settled weather before winter starts a fresh assault on the country.

Vast swathes of New Zealand are set to be drenched as a complex low conjures up days of rain, gales and even snow for the South Island.

Tonight's clash between the touring British and Irish Lions and Chiefs in Hamilton will escape the coming deluge, but MetService meteorologist Andy Best is warning the upper North Island is due for a hammering when winds starting to pick up tonight.

First weather warnings were issued mid-morning for Northland, Auckland and southern Westland, where the weather is expected to drastically deteriorate within 24 hours.

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Tomorrow severe gales are likely to be pounding the Far North and the following day the entire upper half of the island will be buffeted. Gales will not die down until Friday.

Best says along with the winds it was going to be an extremely wet along the eastern coastline of both islands and the West Coast of the South Island as moisture-laden tropical air caught up in the complex low moved south.

By Thursday virtually the entire country will be under a storm cloud. Bay of Plenty, Auckland, Northland and Canterbury are expected to be the worst affected.

Niwa is expecting up to 62mm and 60.8mm of rain to fall in Whangarei and Kaitaia on Thursday and 21.8mm for Auckland.

Snow was expected to fall down to 500m in Canterbury on Thursday and Friday, affecting alpine roads for the second week running.

Best said the stormy weather was expected to track across the country on Friday but will be followed by a chilly southwesterly change sweeping up the country over the weekend.

But before then, the upper North Island would bask in spring-like temperatures thanks to the tropical air spilling from the complex low.

"For this time of year it's still warm. Just a day after midwinter's day it'll be 18C in Auckland."

Ironically the West Coast and Fiordland looked like the driest areas for the last day of the working week.

The weather was expected to clear across the rest of the South Island for the weekend to leave cold, frosty mornings.