A motorbike rider was thrown into the oncoming traffic lane after a collision in South Windsor yesterday (Wednesday).
Hawkesbury police stated the incident occurred on George Street about 6pm on January 22.
"From information known to police at this time, it appears the [Hiace] van has been stationary on the side of George Street when it has commenced to merge into the traffic lane, colliding with a motorcycle," police stated.
"The rider has attempted to avoid the collision however the two vehicles collided causing the rider to be thrown from the cycle ... in the oncoming traffic lane."
The motorcycle rider was treated at the scene for serious leg injuries and taken to Westmead Hospital, where he remains in a stable condition.
The van driver was breath tested at the scene and returned a negative result.
Police have issued a call out for witnesses who have not already provided their details to contact Windsor police station on 4587 4099, or Crime Stoppers on 1800 333 000 and quote event number E73267236.