Detours have been put in place after a serious vehicle crash near Culverden in North Canterbury resulted in the closure of State Highway 7.

 Police were called to the single-vehicle crash between Long Plantation Road and School Road, around midday today.

Initial indicators were that there were critical injuries, police said

A detour is available via Long Plantation Road and School Road. Delays should be expected for those travelling in the area.

Road users should avoid the area or delay their travel if possible, as the road is expected to be closed for some time for emergency services to do their work.