A man with serious injuries was taken to hospital by ambulance after being cut out of a vehicle.
Seven other people were involved in the crash and had either minor or no injuries, a St John Ambulance spokeswoman said.
One northbound lane of the highway was closed as debris scattered the road for 100 metres.
Motorists were advised traffic would be delayed for about an hour.
Earlier, at 5.45pm, a male pedestrian was critically injured when he was hit by a car in Albury, 46km northwest of Timaru.
The man suffered multiple fractures and was taken to Timaru Hospital by St John.
The official road toll period began at 4pm today and ends at 6am on Tuesday.
Over Queen's Birthday weekend last year, five people were killed in five separate road incidents. Three were drivers and two were passengers, one of whom was on a motorcycle.
There were also 96 crashes which caused injury, including 28 people who were seriously hurt and 109 who suffered minor injuries.
Traffic began building up on Auckland's Southern Motorway this afternoon as holidaymakers headed out of the city.
Superintendent Steve Greally said while police wanted New Zealanders to enjoy themselves this long weekend - the last public holiday until October - they also wanted to make sure safety was put first.
"It only takes a split second to lose control of a vehicle in wet or icy conditions."
Police have confirmed that the scene of the crash on State Highway 1 north of Kaiwaka is now cleared and all lanes are open.
