Gale force winds are forecast for the central North Island and parts of the South Island is covered with a blanket of snow.
Civil Defence has issued a wave warning for this afternoon and evening for Whanganui through to Ōtaki, particularly at high tide at 5.30pm. It said people should stay away from beaches.
It has also issued a strong wind warning for Wairarapa till this evening, with northwesterly gusts of up to 140km/h expected in exposed places.
MetService said a watch was also in place for severe northwest gales in Hawke's Bay, as well as in Marlborough, Wellington and the Canterbury high country.
The South Island passes were affected by snow this morning, although all except the Haast Pass - which links the West Coast with Otago - are open.
The road from Te Anau to Milford Sound will be closed all day, with the next update not expected until tomorrow morning.
There is also a warning about high sea swells north of Hokitika and around Bruce Bay in South Westland, along State Highway 6.
If conditions worsen the road may be closed overnight.
Crown Range Road in the Queenstown Lakes District has also been closed due to snow, which has continued to fall in the area.
Queenstown also got a dusting this morning.— MetService (@MetService) May 23, 2018
A heavy snow warning is in place for Fiordland, Westland south of Haast, Southland north of Mavora Lakes and western Otago ranges south of Mount Aspiring.
Damage to trees and powerlines is also expected.
Queenstown bore the brunt of it and schools in the area had a late start this morning.
The Queenstown Lakes District Council said drivers need to take extreme care.
Spokesperson Jimmy Sygrove said tailgating, and passing trucks that are clearing and gritting the road, is a fairly stupid thing to do.
He said anyone who saw such behaviour should report it to the police.
Further north, the Desert Road was closed this morning between Waiouru and Rangipo due to snow and ice, but has now reopened.
The road closures come after a cold night with temperatures hitting as low as -2.3°C in Timaru and -3°C near Pukaki.
MetService meteorologist Tom Bell said there are a few more cold nights on the cards due to a south-west flow over the country.
"The cold will continue through the next few days and into the weekend."
Mr Bell said a heavy snow warning remains in place tonight and that the snow - 20cm to 40cm - was expected above 400m in southern parts of the country.
Higher parts of the South Island would be most affected by the colder temperatures, he said.
However, Mr Bell said next week should be a lot drier with less rainfall.