Northlanders are being warned to batten down the hatches today as heavy rain and strong winds sweep the region and possibly bring flooding.

East coast boaties are particularly urged to keep an eye on weather conditions, as a deep sub-tropical low heads down the country.

MetService meteorologist Daniel Corbett said the low was due to hit Northland before noon today, with up to 90mm of rain expected over 10 hours and winds gusting up to 120km/h.

He said after the heavy thundery downpours that moved across many parts of New Zealand over the weekend, yesterday provided only a brief respite from the weather, with the outlook for the rest of the week pretty bleak.


"Your people should really batten down the hatches up there.

"It's going to be pretty wet, windy, messy and yucky."

Mr Corbett said between 60-90mm of rain was forecast to hit Northland between about 11am and 9pm today, while severe gales could gust up to 120km/h and potentially cause damage to parts of the region, with the eastern parts most at risk.

"This major low will carry an abundant supply of tropical moisture with it, bringing a heightened risk of flooding, especially across northern and eastern regions," Mr Corbett said.

"The wind of 120km/h is getting up to where it could be causing damage.

"It will also bring a significant swell, which means it's going to be pretty horrible for those offshore on your east coast [today] and overnight."

People should avoid going on to the water today if they did not need to, given the probable turbulent conditions, Mr Corbett said.

The rain and wind will stick around tomorrow, but are unlikely to be anything like as bad as today.

The intense low will gradually weaken during Thursday.

"But one bright spot is that it won't be cold and there will be highs of 17C or 18C over the next couple of days, then up to 20C on Friday, which will also likely bring a few showers. Then you should have a fairly good weekend, or at least one much better than your last weekend."