Parts of the country are in line for periods of heavy rain and snow, with snowfall warnings in effect across the South Island mountain passes

State Highway 80 from Lake Pukaki to Mount Cook, and State Highway 8 between Omarama and Fairlie are closed.

An orange rain warning has been issued for Clutha, Dunedin and North Otago.

An orange snow warning is in effect for Dunedin, the hills of eastern Otago, the South Canterbury high country and the foothills south of the Rangitata River.

Interislander has preemptively cancelled some of tomorrow morning's sailings due to forecast rain and swells.