Snow has closed the Rimutaka Hill road between Wellington and Wairarapa, leaving 10 vehicles stranded this evening.
Police central communications spokesman Marc Clausen said said there were only "a couple of inches" of snow but the road was quite icy.
A police 4WD vehicle was still on its way to the stranded motorists as of 8pm.
"We've closed the hill, we're just going to try and get to the top and sort out whether we can get these people down or not," Mr Clausen said.
"If need be, we can just leave their cars there and ferry them down."
It was not known exactly how many people were stranded.
Contractors were also on their way, but it was too soon to say when the road might reopen.
"I'm not sure when the snow showers are going to pass, and then I guess we've got ice to deal with if it gets any cooler."
Mr Clausen said the Desert Rd was also shut from Taihape to Rangipo due to snow.
Fire Service communications centres in the North Island said there had been reports of trees and power lines down, but no major weather-related events.