Police are investigating a crash at Middleton this afternoon.

About 12.20pm on Thursday 17 April, police responded to reports of a crash between a cyclist and van.

The cyclist, a man aged in his 70s, sustained serious injuries in the crash and was taken to hospital. He is expected to be airlifted to Adelaide for treatment.

The driver of the van was not injured and is assisting police with the investigation.

Anyone with information on the crash is asked to contact Crime Stoppers on 1800 333 000.