MetService is warning of more snow on the way for many South Island alpine passes.

In Arthurs Pass between now and 4 in the morning, there'll be about 6-12 cm of snow, followed throughout tomorrow into the evening by a further 6-12 cm.

In Lindis Pass, some 12-18 cm of snow is likely from later this evening until midnight tomorrow night.

Lewis pass can expect 5-10 cm of snow near the summit overnight tonight, with a further 5-10 cm through the day tomorrow.

On the Milford Road, up to 10 cm os snow is likely between now and midnight, then as much as 20cm could fall between midnight tonight and tomorrow evening.