SH1 closed after four-car crash

State Highway 1 near Greta Valley, 95km north of Christchurch, has been closed following a four-car smash.

One woman suffered serious injuries in the 12.40pm crash, 1km south of Greta Valley, and was flown to Christchurch Hospital.

The road was closed at 12.55pm, with a detour in place through Scargill Valley to SH7. It was expected to reopen at 6pm.

Two men and two children were moderately injured and taken to Christchurch Hospital by ambulance, St John spokesman Ian Henderson said.

Eleven other people suffered minor injuries were treated and assessed at the scene.

- NZPA