Three people were transported to Christchurch Hospital with moderate injuries.
Motorists are asked to avoid the area if possible. The road is expected to be clear by around 5.30pm.
Meanwhile, State Highway 2 at Rimutaka Hill Rd is closed due to strong wind gusts.
NZTA said motorists should delay their travel over Rimutaka Hill until weather conditions ease.
Metservice's severe weather warning has a forecast of severe northerly gales in the Wellington and Wairarapa regions through to Sunday evening.
Earlier, about 12.10pm a large truck rolled near Tokoroa blocking a lane on State Highway 1 and caused delays.
Witness Aaron Adamson said the truck was empty and thought wind was a factor in the accident.
"He came around the corner and I believe a gust of wind pushed him off the road. It hit the bank and rolled," Adamson said.
"I believe it was the wind because I've been getting blown around in my truck today."
A Fire Service spokesman said the driver complained of a sore neck and was taken to hospital.