MetService spokesman John Law said southern parts of the South Island, Banks Peninsula and eastern parts of the North Island could expect showers for the rest of the week.
New Zealand continued to be on the eastern flank of a broad area of high pressure over the Tasman Sea, meaning the south would continue to be affected by wind, and showers would fall in other parts of the country, Mr Law said.
Snow showers were expected for Southland and Otago tonight, as well as the Banks Peninsula and coastal parts of Canterbury.
Snow showers were also expected for the North Island, above 300 metres in Wellington and Wairarapa from around 6pm.
A severe weather warning had been issued for Wellington, Wairarapa, Wanganui and Taihape, and the cold weather meant road closures could be expected.
Snowfall would affect Dunedin's Northern Motorway overnight, and the Desert Road and the Rimutaka Hill Road were also likely to experience fresh snowfall tonight, said Mr Law.
NZTA spokesman Anthony Frith said the Rimutaka Hill Road could close if snowfall created a risk of it being impassable and unsafe for drivers later this evening.
Contractors were monitoring the road, Mr Frith said.
"Closed or open we ask motorists to take care on all roads because in this kind of weather they can get icy and slippery."
Motorists should check the NZTA website before travelling, he said.
