Motorists need to use chains in snowy conditions on Lewis Pass, Arthur's Pass and Porters Pass, says the New Zealand Transport Agency.
MetService says about 2cm of snow fell on Arthur's Pass overnight, but the road is clear.
Snow has now stopped falling on the three high country passes in the South Island, but the Transport Agency says chains are essential for people driving there today.
Arthur's Pass is closed to towing vehicles due to the conditions.
More snow is expected to fall to 1400m on Arthur's Pass tomorrow morning and night.
MetService is also predicting snow to 1100m in the Canterbury high country at times tomorrow.