Black ice caused at least seven motor vehicle crashes around Dunedin this morning and delayed flights at the international airport.
Senior Sergeant Bruce Ross said five of the seven reported crashes occurred within half an hour, between 6.40am and 7.10am.
Two occurred on Brockville Rd, one on State Highway 1 near Evansdale, another on SH87 near Outram, one on Kaikorai Valley Rd and two on Brighton Rd.
Police said one of the crashes, in which a small truck collided with a lamp post in Brockville Rd about 6.40am, was serious.
The male driver sustained some injuries and was taken to Dunedin Hospital. The extent of his injuries at this stage is not known.
The incident caused major damage to the vehicle.
Snr Sgt Ross said black ice was widespread throughout the city, as rain overnight froze early this morning.
Dunedin Road Policing Manager Senior Sergeant Phil McDouall says drivers setting out in the early morning in particular need to be careful on the roads.
"There is a lot of ice around on these bright, frosty mornings and it does require drivers to be patient - drive very slowly and where possible use main routes in the city that are gritted."
At the Dunedin International Airport three flights between Dunedin and Christchurch were cancelled and others delayed because of ice.
According to MetService it was 3.9degC in Dunedin at 6.30am, but felt like 1degC.
Meanwhile, white-out conditions have closed the Desert Rd in the central North Island and eastern regions are experiencing some of the coldest weather of the year.
MetService has issued severe weather warnings for Hawkes Bay, Taihape and Wairarapa, with heavy rain warnings in place for eastern parts of the North Island.
From midday, 100-150mm of rain was expected, with 200-250mm about the Kaweka and northern Ruahine Ranges and the Hawkes Bay foothills west of Napier, the forecaster said.
WeatherWatch forecaster Philip Duncan said the eastern North Island could experience some of the coldest weather of the year.
"A low has stalled over the North Island and will remain there for the next few days," he said.
"It's going to bring rain into places that didn't really get it last week... Bay of Plenty, Gisborne, Hawkes Bay, all those areas are going to be stuck with this low for the next few days. It's going to be cold with rain."
Snow had closed the Desert Rd in the central North Island with snow to 700m and "white-out" conditions, Mr Duncan said.
"You've got a gusty wind blowing snow about and you can't see much.
"The way the temperatures are the snow could linger. This could be potentially good news for the ski fields in the North Island which have really missed out this winter."
