Drivers crossing the Lindis Pass are being advised to carry chains, with the NZ Transport Agency saying snow and ice is likely on the road.
An earlier warning that snow had made chains essential for the Lindis Pass, on State Highway 8 between Cromwell and Omarama, was removed around 7.15am.
Snowfallls are expected on other South Island passes this morning, while high winds are also causing concern for drivers on SH6 between Harihari and Haast.
Around 7.30am, NZTA said care was required by campervans, caravans and other high-sided vehicles on that section of SH6, particularly in river valleys.
Around 8am MetService said that by 1pm up to 3 centimetres more of snow could accumulate near the summit of Porters Pass on SH73 between Canterbury and the West Coast.
On the Lewis Pass on SH7, also linking the West Coast to Canterbury, around 1cm of snow could accumulate near the summit by 1pm.
Some snow also fell on the Milford road on SH94 overnight.