A 21-year-old woman was seriously injured after the car she was in struck the back of a stock truck in Southland early this morning.

Emergency services were called to the crash on State Highway One at Edendale Hill, west of Edendale, at 6.45am.

The crash involved a Mazda MX6 car travelling west towards Invercargill which struck the rear of a Ford stock truck which was ascending the hill at low speed due to the incline.

The 21-year-old female passenger sustained serious injuries and the 27-year-old male driver received minor injuries. They were both taken to Invercargill Hospital.