Parts of the South Island are on alert as a severe weather warning remains in place for heavy snow to low levels in South Canterbury.
MetService said it was snowing at weather stations 200m or more above sea level.
There are road snowfall warnings for the alpine passes and the Transport Agency said drivers should be careful on State Highways 6, SH94, and SH87 this morning.
At this stage all major South Island roads are open.
Fulton Hogan said black ice was forming in isolated areas in Maniototo as temperatures dropped and extreme caution was advised.
Queenstown Lakes District Council said the Crown Range had packed snow from overnight falls but it was gritted and the road was open. Motorists should carry chains in case conditions changed.
The council warned across the rest of the district temperatures were between -2°C and 4°C with the potential of ice forming.
Winter driving conditions, including slippery areas anywhere roads are shaded and over bridge decks, are to be expected.