Snow has closed roads in the south and strong wind forced speed restrictions on the Auckland Harbour Bridge as severe weather sweeps the country.

West to southwest winds in Auckland could approach severe gale in exposed places, MetService said.

Reduced speed limits are in place on the Auckland Harbour Bridge, and Waka Kotahi said lane reductions might be required.

The agency advised motorists to take extra care, with high-sided vehicles and motorcycles most at risk.

Roads are closed and severe weather warnings are in place elsewhere in the country as a strong northwest flow covers central and southern New Zealand.

MetService issued orange strong wind warnings from Wellington and Wairarapa to as far south as Dunedin and Clutha, while watches are in place for Auckland, Great Barrier Island and Coromandel Peninsula.

Snow in the South Island closed Arthur's Pass (SH73) Lindis Pass (SH8) and the SH7 Hanmer Springs turnoff to Springs Junction.

Arthur's Pass (SH73) early on Wednesday morning. Photo: Waka Kotahi

State Highway 94 to Milford Sound has been closed since Sunday but Waka Kotahi said it may reopen on Wednesday morning after avalanche-control work.

In the North, the Desert Road and the Remutaka Hill Road are under road snowfall warnings.

This article was originally published by RNZ