Following days of gales, heavy snow and some thunderstorms across much of the country, mostly fine weather is expected over the weekend.

About 1700 homes were without power in Southland on Tuesday night and roads across the South Island and the Desert Road, central North Island, were closed earlier in the week due to heavy snowfall.

On Thursday power had been restored to most properties and only State Highway 94 through Arthur's Pass from Cascade Bridge to Milford Sound remained closed, but this was due to reopen at midday.

On Wednesday motorists were warned to be extra cautious due to ice on the roads, which is thought to have contributed to a number of accidents, including 10 in the Tasman District.

A two-car crash closed SH6 between Blenheim and Nelson on Wednesday afternoon. Two people were seriously hurt.

But after heavy snowfall in many areas from Monday to Wednesday, the Metservice is predicting mostly fine weather across the country on Friday and Saturday, although Gisborne and Hawke's Bay can expect showers on Saturday.

On Sunday it will be mainly fine with some morning frosts, and cloud increasing over Northland, Auckland, Bay of Plenty and Fiordland.

The lower part of the South Island can expect more snow falling to about 500 metres on Thursday, although there will be some long fine breaks in Westland.

Gales up to 120km/h are expected in some parts of Southland and Otago until Friday afternoon.

There is bad news for the Chatham Islands with showers, some heavy hail, thunderstorms and gales expected on Thursday.