Heavy snow has cut off access to Tekapo and Mount Cook Village.
State Highway 8 between Fairlie and Twizel along with State Highway 80 between Mt Cook and Ohau were shut just after midday on Friday as more than 10cm of snow fell. Heavy snow also fell in Tekapo.
Police say 30 vehicles were stranded on the road near the township, and there are reports of two buses skidding from the road. There were no known injuries.
Many tourists visiting the area for a day-trip are stuck there for at least a night.
Staff at the Roundhill Ski Area welcomed the cold weather and over 35cm of snowfall it brought.
Further north near Nelson, heavy rain caused problems with emergency services responding to reports of flooding and trees down.
Police are advising people to stay off the roads as the harsh weather continues.