Second 'significant system' set to bring wintry weather to New Zealand

A second storm is set to hit New Zealand this weekend with the return of wintry conditions and severe weather risks.

Beaches in the Coromandel have taken a recent beating, with high tides and large waves combining to flood roads and suck away over a metre-and-a-half of sand.

Still bruised by that storm, the country now faces a second encounter - this time with a low-pressure system the size of Australia.

"We do have another game-changer on the way and it is quite a significant system," WeatherWatch warns.

"We've got two different significant systems to talk about; one is that low up to the northeast of New Zealand, and the second one is the bigger low coming in for this weekend."

The stormy low off the east coast eases a little on Tuesday and moves a little bit further out to sea. But it roars back with a vengeance on Wednesday.

"It's going to deepen a little bit further tomorrow and actually strengthen those winds again in some areas," WeatherWatch head forecaster Philip Duncan says.

"As that low deepens the swells will start to generate again. It's a little bit of 'one step forwards, one step backwards' because the low itself is moving away, but at the same time it's deepening."

On Thursday, the low weakens while drifting a little closer to New Zealand, which could stop the winds around Auckland while strengthening them around East Cape.

And then on Friday, the low moves further to the east and the winds start to really ease across the North Island, with the possibility of some extra rain pushing back into the very coastal fringes.

But another low is brewing on the other side of the country. A very large and complex low-pressure system will develop over the Tasman Sea and New Zealand this Friday and weekend.

"This is the big low that's forming. It's roughly the size of Australia - I mean it's a pretty big system," Duncan warns.

This may generate heavy eastern rain in the South Island, snow down to low levels, single-digit highs and more windy weather.

"Some early indications are that heavy snow will impact the Southern Alps and Alpine Highways this weekend, with perhaps up to 40cms on the peaks and 1 to 5cm may even fall as low as the Canterbury plains (above a couple hundred metres)," WeatherWatch says.

"Rain in the east of the South Island (Canterbury) may be heavy too. Some early estimates at and show 70 to 90mm possible through inland Canterbury on the plains (like Darfield, for example).

"Winds will also impact the South Island as we go into Sunday. The North Island has milder westerlies until the colder southerlies kick in later Sunday and into next Monday."

WeatherWatch adds it's such a large system some regions will barely be impacted - more details will come later in the week.