Police car hits man, 23, in Alice Springs

A 23-year-old man is in a critical condition in hospital after being hit by a police car that was pursuing him over an alleged crime.

The man was flown to Royal Adelaide Hospital with a serious head injury.

The internal Professional Standards Command will have oversight of the police investigation into the crash.

Police said they responded to a report of a man armed with a knife at a petrol station on Larapinta Drive in Alice Springs.

Numerous police cars attended and in the process of trying to arrest him an unmarked police car hit the man, say police.