Tourists remain stranded in Milford due to road closures after a week of stormy spring weather across the country.

Thousands are still without power in Canterbury, while two southern highways are set to remain closed for at least another day.

It comes after torrential rain and gale force winds lashed southern and central New Zealand this week, bringing down power lines and causing huge slips.

In Milford Sound, about 15 tourists are trapped in their accommodation, without phone reception.


Christine Wallace from the Milford Sound Lodge said they had been "good natured about the situation" and were making the most of having the popular tourist spot to themselves now the wild weather had calmed down.

They are expected to be airlifted out of the area before being taken by bus to Te Anau and Queenstown later today.

"During their stay many [of the tourists] have commented they had never experienced a storm quite like the one we had," said Ms Wallace.

State Highway 94 from Lower Hollyford turnoff to Milford Sound is still closed due to bad weather causing avalanches and slips, NZTA said.

The road has been closed since early on Wednesday morning after damage caused by one of the worst storms seen in the area in 25 years.

A major slip between the gates of Haast Bridge and Haast Pass Summit has also closed State Highway 6 since Wednesday. It will not reopen today.

A 50 metre slip at Diana Falls is the major problem in clearing the road, said West Coast area manager, Mark Pinner.

Further inspections by technical engineering teams have discovered clearing the slip will be "more complex than initially thought", he said.


"One of the major issues is safely bringing down three large boulders about the size of houses that are perched high up on the slip face," he said.

"We need to get assurance that they are stable or if not they will be sluiced or blasted free."

The situation will be reviewed later this afternoon to get a better indication of when it might reopen, he said.

Meanwhile 6500 Orion customers are still without electricity today, predominantly in rural west Christchurch. However, some smaller areas within Christchurch city are also affected, the power company said.

Gale force winds saw 28,000 Orion customers without power on Tuesday night, with the company saying 75 per cent now have electricity restored.

"The extent of damage we are facing is significant and we are continuing to uncover more damage as we progress through our network repair," said Orion chief executive Rob Jamiseon.

"This is not an easy repair and as a result some customers will unfortunately be without power for a few more days. We hope everyone will be back on by end of day Monday but as we get closer to areas like Windwhistle we may uncover even more damage."

He said workers would restore the network from an east to west direction, with a priority on areas with the most customers.

"We appreciate that for customers still without power it is difficult and frustrating, and we thank them for their patience. All available crews are working to restore power as quickly and safely as they can," Mr Jamieson said.

The wintry weather isn't over for the South Island however, with MetService issuing a weather advisory, forecasting snow down to sea level for Southland, Clutha and Dunedin.

A "very cold" southwest flow is set to spread over the southern South Island on Saturday, bringing a return to chilly conditions.

While snowfalls are not expected to be heavy enough to warrant a snow warning, 5 to 10cm of snow may accumulate in Southland, Clutha and Dunedin above about 200 metres, MetService said.

The North Island meanwhile, will see a damp weekend, with showers in most places.