Canterbury, South Canterbury, West Coast and Otago motorists need to watch for ice and grit in shaded areas and bridge decks.
Transit New Zealand urges those driving through alpine passes to carry chains, especially over the Crown Range, where they are essential.
Those traversing SH 94 from the lower Hollyford to Milford Sound are also asked to carry chains due to snow.
Snowy roads saw SH 87 from Outram to Middlemarch closed until about 10am today when Transit lifted its status to "extreme care required" due to ice and at about 11am started allowing towing vehicles through SH 85 from Palmerston to Kyeburn.
Transit New Zealand asks for "extreme care'' to be taken on SH 1 from the Kilmog to Dunedin and SH 1 from Balclutha to Clinton due to snow on the roads.
The Lindis Pass from Omarama to Tarras along SH8 is open but cautions are in place due to snow.
