Warnings of treacherous road conditions in the South Island's Mackenzie Country, after a freezing night

State Highway 8 between Twizel and Fairlie, and State Highway 80 between Lake Pukaki and Aoraki/Mount Cook are now opened after it was closed overnight because of snow and ice.

Mackenzie District Council warns there's still dangerous conditions for motorists across the network.

MetService Meteorologist Surprise Mhlongo says it's been one the coldest mornings of the year for most of the country.

He says snow's still on the ground, with frosty conditions and clear skies in many parts.