A man is being flown to hospital after a jet ski hit him in the head off South Stradbroke Island in Queensland.

A man has been hit in the head by a jet ski off South Stradbroke Island in Queensland.

The 33-year-old man suffered a head injury when the jet ski crashed, just after 10am (AEST) on Monday.

He is being flown to hospital for treatment, the Queensland Ambulance Service says.

Another man was also thrown from the jet ski and is believed to have suffered spinal injuries.