TWO motorcycle riders were injured, one seriously, when their bikes collided during a ride at Silverdale on Sunday.
The two men, believed to be out for the day together, crashed on Silverdale Road shortly before 2pm.
One man, 38 of Clairmont, had spinal damage; the other man, had minor injuries.
Police, ambulance paramedics and a CareFlight trauma team rushed to the scene, where a doctor and the paramedics treated the injured men.
The CareFlight helicopter, which landed in a nearby vacant block, later flew the man with spinal injuries to Royal North Shore Hospital, where he remained in a serious condition.
An ambulance took the other man to hospital for treatment of his injuries.
A CareFlight spokesman said the man with spinal injuries was not in a life-threatening situation but his condition was serious.
"We don't really know at this point how bad it is," the spokesman said.
"Tests will have to be carried out over the next week or two to assess the seriousness of his injuries."
The spokesman said the exact circumstances of the accident were not known.
Police are continuing their inquiries and asked anyone who may have witnessed the accident or who has any other information to contact St Marys police on 9677 7501 or Crime Stoppers.