Canterbury Police are appealing for witnesses to a crash involving two vehicles about 1km north of Orari on State Highway 1 at 5.15pm on Saturday.

Witnesses report a south-bound minibus appeared to have drifted across the centre line and collided with a north-bound grey Toyota Celica.

Nobody was seriously injured in the crash and one lane of the State Highway was closed for a short time while the scene was cleared.

The man driving the Celica was taken to Timaru Hospital. He was treated for two broken ribs and discharged three-hours later.

The female driver of the minibus was uninjured but three of the 11 Burnside High School students on board were taken to Timaru Hospital for treatment of minor seatbelt injuries. One of them was also treated for a chipped tooth.

Acting road policing manager Acting Inspector Phil Newton says both vehicles were written off in the crash.

"However everyone involved in the crash was wearing a safety belt and this contributed to preventing any loss of life and anyone suffering more serious injuries."

"This incident is a good illustration of the benefits of wearing appropriate restraints while travelling on our roads.

He says the students were travelling to Twizel to compete in a rowing regatta being held this weekend.

Nine of the students, including the three treated in hospital, opted to continue their journey (to compete in the regatta) in another minibus hired by the school.

'Internationally it has been proven that wearing appropriate restraints when travelling in a motor vehicle can reduce the number of fatal or serious injuries in a crash by 20 per cent.

"Canterbury schools should be commended for ensuring their students wear restraints when travelling on school trips,” says Acting Inspector Newton.

Canterbury Police appeal to anyone who witnessed the crash, or were travelling in the area, north of Orari on SH1 at 5.15pm and may have seen the two vehicles prior to the crash to contact Timaru Police Station on 03 687 9808.

Information can also be provided anonymously by calling Crimestoppers on 0800 555 111.