MetService is warning snow could fall down to 400m in parts of the South Island on Tuesday, and may close some alpine passes.
Meteorologist Daniel Corbett says 10 to 20cm may fall in parts of North Canterbury and South Marlborough above 400m.
Mr Corbett says motorists should also be aware that the Lewis, Porters and Arthurs Passes could get between 20 and 40cm by Wednesday morning.
