Roads are being closed in the South Island due to heavy snow and a snowfall warning has been issued for the Central North Island.

The MetService has issued a snowfall warning for the Desert Road.

'Expect 2 to 5cm of snow to settle on the road above 800 metres between 5pm this evening and midday Thursday, with lesser amounts down to 600 metres.”

The wintry blast moving up the country is bringing the first big dump of snow this winter – music to the ears of New Zealand's skifields.

Arthur's Pass Cafe and Store manager Michael Bohny​ says the township is "completely white" on Wednesday morning.

"It's the first big dump this year.”

He says the snow started falling about 3am and estimated about 10cm of snow on the ground.

MetService meteorologist Michael Martens says around 5am Wednesday the cold air had started to filter into Canterbury.

Marlborough should expect cold air later in the morning.

An NZTA web cam showed snow at Arthur's Pass, and there was also snow on the Crown Range Road.

'The snow has started and is gradually lowering this morning. Then everything clears from the south, and spreads onto the North Island during the course of the afternoon and evening.”

As the blast moves up the country, temperatures are forecast to drop.

The MetService is forecasting an overnight low of three degrees for Tauranga tonight and a daily high of 12 tomorrow.

Temperatures are expected to increase to about 15 degrees during the day on Friday, with overnight lows of seven forecast.

-Additional reporting by Stuff.co.nz