Temperatures tumbled across the country overnight, with many areas dropping below freezing.

MetService data shows Omarama, in Canterbury's McKenzie District, dropped to -10C, while Invercargill and Christchurch recorded near -3C, Timaru was about -4C, and Queenstown got to around -5C.

In the North Island, Taumarunui had the coldest night with temperatures dipping to -3.9C, while Hamilton dropped towards -1C. Rotorua also dipped under 0C, while temperatures dropped under 6C in Auckland, and got down to about 7C in Wellington. Tauranga recorded 5C around 6.30am.

Police are asking those on the road to take extra care. Conditions were frosty, particularly in Dunedin's hilly suburbs.

Motorists are asked to delay travel if possible, and drive to the conditions.

It comes after police were called to a crash on State Highway 8 where a truck and trailer tipped in icy conditions between Tekapō and Twizel about 12.10am.

A short time later, a second truck crashed into the trailer and tipped over, a police spokesperson says.

'One person had minor injuries, and the road remains closed while grit is spread on the road.”

MetService meteorologist Jessie Owen says the mountainous King Country area and Taihape general area recorded the coldest temperatures in the North Island.

'We're getting well into winter now so averages for the South Island in June for a lot of places are hovering around in the low single digits.

'We've got basically no wind, clear skies and cold air over us which has allowed those temperatures to drop so low overnight.”

Weather conditions are forecast to be similar overnight on Wednesday across the country.

'We had a pretty mild start to winter this year and it's hit us with a bang in the last few weeks so I think everyone's feeling it, it's a bit of a sudden change.”

A few showers in the eastern regions of the North Island would clear throughout the day and into Thursday.

From Thursday afternoon onwards, more unsettled weather were forecast with a few fronts bringing rain.

'That will also bring some warmer air with it and clear out some of these colder temperatures, briefly anyway before the next cold break arrives.”

-Stuff/Hannah McCullum.