Snow is forecast to fall over alpine routes in the South Island until midday on Sunday.
Up to 50cm may accumulate on the top of the Lewis Pass and even heavier snowfalls could occur at Arthurs Pass.
State Highway 73 to Otira is closed to towing vehicles and chains are essential for others.
Up to 80cm of snow could accumulate on top of State Highway 94, to Milford from Te Anau and it remains closed.
Up to 30cm of snow is forecast at Lindis Pass while up to 15cm may fall at Porters Pass.