Gale force winds of up to 200km an hour blew some young skiers uphill and smashed car windscreens on Mt Hutt.

The only road off Mt Hutt ski field has reopened, freeing 1200 skiers who spent last night camping out in alpine cafes.

About 1200 skiers - including several hundred schoolchildren - were trapped overnight when winds of more than 200km/h hit the mountain.

The road off the mountain was reopened at about 9.30am. The stranded skiers were briefed and given an energy drink before their descent down the mountain.

Skiers coming off Mt Hutt were mostly positive about the experience.

Australian Jane Fullerton-Smith said the winds at the skifield were "insanely strong".

"It was pretty terrifying," she said.

Her children Ella, 5, and Charlotte, 7, were skiing for the first time and the wind was so strong that they were being blown uphill.

Christchurch woman Alexandra Blair described the night as "like being at a teenage girls sleepover".

"The kids were awake pretty much all night and are pretty hopeless today," Ms Blair said.

Australian Adele Likvarn said she spent the night on a cold concrete floor and got no sleep but she was still upbeat about her experience.

She said she met heaps of people, including one man that she plans to meet later for coffee.

"I didn't hear anyone else having too much of a grumble. These things happen, don't they?"

She said skiers had been told that some wind gusts were in excess of 200km an hour.

"It was a real gale last night. We were quite scared. You couldn't go out or you would be blown away," Ms Likvarn said.

She praised the Mt Hutt staff for their hospitality.

Audrey Hume, 16, is a member of a US ski club and said it was simply a matter of making the best of the situation.

"It was really crowded, lots of people. It got really stuffy. People were just passed out all over but they fed us a decent dinner for how many people they had to supply," Ms Hume said.

She said it was difficult to find an area of your own to sleep.

"I actually slept outside for a little bit," Ms Hume said.

Another skier, who did not give his name, was highly critical of the management at the ski field.

"There was no communication so no one knew what was going on," the man said.

John Van Ameyde said he spent time sleeping on the floor, the bar and on chairs.

"Interesting angles all over the show. It was certainly a memorable experience," Mr Van Ameyde said.

He said the stranded skiers were fed a hearty meal of beef stroganoff and wedges last night and bacon sandwiches this morning.

"It's not something you would want to do but it was not a bad experience," Mr Van Ameyde said.

The winds have died down and even the rain has now eased but the weather blast that hit Mt Hutt is only a precursor to a wild front expected to strike the rest of New Zealand today and tomorrow.

'Chaos on a stick'

One skier last night described conditions in Mt Hutt's packed cafe as "chaos on a stick".

The ski resort - which has had a string of incidents this year, including three deaths - was hit by winds so strong that cars were shaken violently and people venturing outside to use toilets were blown over.

Skiers told the Herald they were called in about midday yesterday as the high winds suddenly hit.

The gales, which caused whiteout-like conditions, closed the only access road to the skifield.

Yesterday Mt Hutt and MetService staff had said the winds were unlikely to ease, and late last night the trapped skiers were making themselves as comfortable as they could in the alpine cafes.

Better news this morning

However Mt Hutt assistant manager James McKenzie said this morning that there was some good news for them to wake up to, with a drop in the winds.

Mr McKenzie said skiers were served bacon and eggs this morning, free of charge, and everyone should be off the mountain by mid-day.

He said last night skiers tucked into stroganoff, pizza and burgers.

"We have to be careful about the amount of food we have because we have some 1200 people," Mr McKenzie said.

He said people were charged a nominal fee of $2 for dinner to make sure there was something left over at the end of the night.

After their meal, the skiers entertained themselves with impromptu quizzes.

Mr McKenzie said the cafe went quiet at about 10.30pm.

"There were a lot of people in a tight place, there was a lot of spooning," Mr McKenzie said.

He said one or two people are worried about missing flights this morning and some school students are homesick.

"It was nothing we couldn't deal with," Mr McKenzie said.

Last night Skifield manager David Wilson said: "People are being awfully good. Everyone's looking after each other and they're bedding down in the cafes, one upstairs, one down."

Among those packed into the facilities were 300 children in school parties and other youngsters accompanying parents on winter-holiday trips.

Speed of high winds a surprise

High winds had been forecast yesterday, but one staff member said they weren't expected on the mountain until much later in the day.

The speed at which they arrived had been unusual.

Aucklander Matt Hooker, on his first trip to the mountain, said the winds were so strong that people were not allowed to leave the cafe.

Those who did have to venture out to use the toilets had to hold on to ropes, and young children were carried to the bathroom.

"The wind apparently has been gusting at around 206km/h at the peak and they have to wait until the wind is below 100km/h to get people down around the base area."

The 24-year-old said he had been sitting in a car - one of many in a queue at the carpark - waiting to see if the road would open, when the weather deteriorated even further.

"The wind lifted the car right up on its suspension, which was a bit scary.

"It was really shaking all the vehicles ... They moved everyone into the cafe after that."

Another skier told Radio New Zealand he was expecting a sleepless night.

"It's certainly not a dorm. Add to that the fact this place is full of Year 7s from the local school and you've got chaos on a stick."

Rough weather set to rock New Zealand

Skifield management said conditions would be monitored constantly, and the road would be re-opened if there was a break in the weather.

MetService this morning is forecasting that the wind and rain will ease. The Northwesterly which had been as high as 200km an hour will die down to 60km an hour above 2000 metres this afternoon.

Forecaster Andy Downs said last night the strong northerly flows would bring heavy rain to the ranges and the West Coast of the South Island overnight.

"Trampers will need to be aware of rising rivers, and the headwaters of rivers feeding into Otago and Canterbury will be getting some reasonable falls."

The front would target the northern part of the South Island, particularly the higher parts of Nelson and Richmond, Mr Downs said.

"There'll be some reasonably good falls even in lower-lying areas there, so there'll be water on roads. That will add to the sodden conditions of this area, which has already received a fair amount of rain recently."

The Mt Hutt closure follows several months of bad luck for the skifield. Three people have been killed and one seriously injured in skiing and snowboarding accidents.

On Tuesday, the field was closed after an avalanche which partially buried several skiers. No one was injured.