More frost and chilly temperatures forecast for much of the country

Frosts and chilly temperatures are forecast for much of the country Wednesday as a polar blast lingers.

Frigid air flowing from Antarctica brought snow to low levels in Dunedin and Christchurch on Tuesday, closing roads and schools, and Wellington had a rare flurry of snow.

MetService meteorologist Katie Lyons said the snow was set to ease on Wednesday but the cold snap would continue.

"This polar blast of air that we've had continues to sit over the country. The entirety of Aotearoa is experiencing below average temperatures with snow still lingering around the east coast and southern coast of the North Island as well as the northern part of the east coast of the South Island for some early parts of the morning," she said.

"Christchurch could see some snow about Banks Peninsula, about the higher ground, but the city itself will see those sleety showers easing off.

"Wellington will see some sleety showers and some snow about the higher hills suburbs."

Lyons said Mount Cook could hit a freezing temperature of -11°C early morning Wednesday.

Queenstown was forecast to be -4°C and Dunedin -3°C, she said.

Lyons said motorists should take extra care on icy roads and watch out for black ice.

"Even for places that don't have snow, which is the majority of the country, we've still got frosts, quite a few of them severe all around the place as well as the potential of icy roads," she said.

The Transport Agency said people travelling between Wellington and Wairarapa should delay their travel, or use the much longer alternative route via SH57 and SH1.

Lyons said the polar blast was set to stick around for a few days.

"The next couple of days will continue to feel chilly ... through about the end of the working week and then there'll be a return to more normal winter temperatures. I don't want to call them warm, but it'll feel much warmer than what we've got now," she said.