Desert Road closed as polar blast lashes central North Island

A blast of cold Antarctic air is set to cover much of the country on Tuesday, bringing with it snow and wind that Metservice warns could cause havoc across the central North Island.

Metservice has issued a heavy snow watch for a chunk of the central North Island including Raetihi, Ohakune, Waiouru and Taihape.

According to the forecaster, the most significant falls are expected between 11am and 5pm on Tuesday.

"We're looking at a very cold southerly flow today over much of the country, and that's certainly going to be seen across the central North Island," meteorologist Angus Hynes said.

"As some parts of the country have seen this morning, snow is obviously going to be one of the effects of that, with snow expected to fall as low as 300m in some places around Ruapehu and Taihape."

As a result of the forecast snowfall, State Highway 1/Desert Road was closed shortly before 4am on Tuesday, with large build-ups of snow and ice expected throughout the day.

Shortly before 9am, State Highway 4 between National Park and Tohunga Junction was also closed, with the same build-up of ice and snow proving a concern for motorists.

The road subsequently reopened later on Tuesday morning, with Waka Kotahi warning motorists to be aware of snow and ice on their journey.

Ruapehu Mayor Don Cameron was holed up in his Horopito home on Tuesday, saying he made the call to work remotely due to the conditions.

"It was snowing pretty heavily this morning but it's eased up now. We're supposed to expect some more later this evening, but right now the sun is shining and it's settled down."

Snow is also falling near Whanganui on Fields Track and Whangaehu Valley Rd, but the Whanganui District Council says the roads are still passable.

But when it came to travelling any further north, Whanganui District Civil Defence Emergency Manager Tim Crowe said his advice was simple.

"The Desert Road is shut, and there is snow falling in Ohakune. There's a heavy snow watch in place for the central plateau. It's not a day for attempting to travel northwards."

Wild winds early on Tuesday morning left a tree covering the footpath on Harrison St in Whanganui. Photo / Bevan Conley

In Whanganui, strong winds resulted in a tree falling onto the footpath in Harrison St on Tuesday morning.

Fire and Emergency New Zealand was alerted to the incident just after 8.30am.