Weather: Snow, rain and gales on the way

Heavy rain and severe gales are on their way, forecasters have warned, brought in by a low in the Tasman Sea.

Northland and Auckland will be in the firing line from Wednesday morning, followed by Tasman District that afternoon.

"A front associated with the low brings brief heavy rain to northern parts of the country with thunderstorms and localised downpours possible," MetService said.

Heavy rain watches are in place for eastern Northland, south of Karikari Peninsula from 6am until 4pm, and Auckland/Great Barrier Island from 11am until 7pm.

There was a moderate chance of each being upgraded to warning level.

"Meanwhile a front moves quickly up the South Island on Thursday and severe gales are possible for parts of central New Zealand," MetService said.

Inland parts of Tasman, west of Motueka, should expect heavy rain from midday Wednesday through to midnight.

There was also a road snowfall warning for Milford Road/State Highway 94 from 10am Wednesday.

"Much colder conditions are expected for the South Island on Thursday with heavy snow for higher elevations, particularly for north Canterbury and Marlborough," the forecaster said.

"Rain is expected to turn to snow about the road late Wednesday morning", with 1cm expected near the summit down to 600m.

"A further period of snow showers is expected on Thursday morning."

Meanwhile in the capital, strong winds were forecast from midday Thursday through to Friday morning.

"Damage to trees, powerlines, and unsecured structures possible," MetService said.

"Driving may be difficult, especially for high-sided vehicles and motorcycles. Prepare your property by securing items that can be picked up by strong winds. Drive cautiously."

The next updates were due at 9pm Tuesday.