Cyclist critical after Helensburgh crash

A cyclist is in intensive care after being struck by a vehicle south of Sydney.

The 58-year-old man was riding south on the Old Princes Highway at Helensburgh about 6.15am (AEDT) on Sunday when he was hit by a vehicle, police say.

He was found injured next to the road by a group of cyclists a short time later.

The man was treated at the scene for suspected fractures before being taken to St George hospital.

Police have appealed for anyone who may have witnessed the incident to come forward.

They are particularly interested in speaking to the driver of an older model white Ford Laser with Victorian registration and green P plates.