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.