A number of Westland students may have to spend the night in a motel due to heavy rain battering the region.
Flooding has closed State Highway 6 from Fox Glacier to Hokitika on the West Coast of the South Island.
West Coast authorities are on high alert and have closed schools as a precaution.
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West Coast Civil Defence public information manager Andy Thompson told Newshub the message for parents is to pick their children up and take them home.
Pupils at South Westland Area School that cannot be picked up by their parents will be accommodated in Harihari overnight.
A welfare centre has also been set up in Harihari for tourists and locals who need support.
Westland Mayor Bruce Smith spotted a campervan submerged in water in the Hokitika River.
MetService is predicting heavy rain and gale force winds for much of the South Island on Thursday.
Between 200 and 250 mm of rain could accumulate on the main divide. Peak intensities could see between 25 to 35mm of rain falling per hour.
People are advised to keep an eye out for slips and flooding caused by the exceptional amounts of rain.
In addition, northwest gales are expected to batter the Canterbury High Country. A strong wind warning is in place where gusts could exceed 150km/h in exposed places.
A wind warning is also in place for Marlborough, Wellington and southern Wairarapa where gusts could exceed 130 kph.
In Hokitika there had been 807 lightning strikes within 20 minutes at around 9am on Thursday.
There are road snow warnings in place for much of the major South Island passes including the Porters Pass, Lindis Pass, Arthurs Pass and The Crown Range.
Between five and 10cms of snow could accumulate on some of the passes early on Friday morning, MetServices says.
Further north, for Aucklanders and those on the North Island's west coast thick tropical air with humid temperatures gave many a terrible night's sleep. Temperatures only dropped to a warm 17C in Auckland overnight.
Flights have been grounded in New Plymouth due to heavy fog and low visibility, an Airport spokesperson says.
Travellers are advised to check with their airline regarding delays or cancellations.
People are advised to stay up to date with the latest forecasts and warnings that may be imposed in their area.