Police today warned motorists to drive to conditions with ice and low fog lingering near Dunedin in the Outram and Taieri areas.
There had already been a car crash in Outram around 8.15am with those inside the vehicles suffering minor injuries.
Those travelling on the slippery roads were told to go slow, increase following distances and take extra care.
Best said the fog impacts the fuselage of the aircraft as it is so cold, however by 8.45am flights were running only slightly behind.
The fog was still lingering around the runway and airport periphery, he said, however visibility had lifted to about 7000m.
Invercargill also experienced some freezing fog early this morning which wasn't unusual for this time of year, he said.
Temperatures in the North Island were mostly double figures overnight - although being pelted with a cool southerly Wellington recorded 10C along with Hamilton while Auckland had 12.4C.
The NZ Transport Agency was reporting ice on several roads in the South Island this morning including the State Highway 6 in the Kawarau Gorge and Milford Rd SH94.
Queenstown-Lakes District Council also tweeted about black ice on its roads including the Glenorchy to Queenstown road.
Best said the North Island can expect some more fog overnight tonight including at Masterton, Whenuapai and Whangarei, however the country's fog capital - Hamilton - was fog-free, instead waking to calm cloudy conditions.
The forecast for the rest of the week was looking a bit showery in the North Island, however the eastern coast from Gisborne to Wairarapa should see finer conditions tomorrow and Wednesday after getting saturated overnight.
On Thursday, there were will be showers on the west coast, from Auckland to Taranaki but it will be clear in the east. However, it's looking to be a wet start to the long weekend with showers expected in most areas on Friday.
The South Island's period of settled weather is about to implode as a series of "active fronts" head over from the Tasman.
Unfortunately they won't be bringing any snow, Best said, with rain forecast on the West Coast and showers on the East Coast.
The rain and showers will continue into Thursday - apart from Canterbury, Dunedin and North Otago - and there will be a few showers still hanging around on Friday.
