KEY POINTS:
Police are warning of treacherous roads in the south of the South Island, saying widespread black ice presented a danger to motorists.
Further North, the Metservice had issued a severe weather watch for Northland, which is likely to be upgraded to a warning later in the day.
A low pressure front coming from the Tasman Sea will bring gale-force easterly winds to the East Coast, from Coromandel northwards.
Metservice forecaster Allister Gorman warned of possible damage to boats, roofs and trees. There was also the risk of flooding and slips caused by heavy rain.
Widespread rain was forecast over the top part of the country, down to Waikato, he said.
Invercargill police said a number of minor, non-injury crashes had been reported on Southland roads this morning.
Rain, sleet and snow yesterday and overnight had frozen onto the roads.
Southland police advised motorists to avoid unnecessary travel, or if going out, to leave early and allow themselves plenty of travel time.
In Dunedin, heavy snow and ice stopped police from driving to a job, forcing them to attend on foot.
A spokesman said officers had to walk to the routine bail check earlier today, he said.
Fire crews in Dunedin, Christchurch and Invercargill were stretched by floods caused by the cracking of frozen water pipes, The Press reported.
Yesterday, the Fire Service received over 100 calls to homes, businesses and schools flooded by cracked pipes from sprinkler and heating systems.
Dunedin senior fire station officer Dave Marsh urged people to insulate exposed water pipes, after an off-duty crew was called back onto the job to help with the spate of floodings.
Mr Gorman said the freezing conditions in the South Island were being driven by a high pressure system over the island.
The clear skies overnight made temperatures drop.
"Yesterday, the temperature recorded at the Dunedin Airport was -8.5C. This morning, it was -2.1, and while quite a bit warmer, any air temperature below zero means freezing on the roads is a risk," he said.
- NZPA