Police and emegency services remain on the scene of a fatal crash on the M4 Motorway at St Marys.
The crash happened earlier this morning and it is understood it involves a car and a motorcycle.
One westbound lane remains open, but there are extensive delays and traffic is continuing to build.
“There is no forecast available as to when all three lanes will reopen due to investigations conducted by NSW Police into the cause of the incident,” a spokesperson for the Traffic Management Centre said.
“Motorists are advised to exercise caution, expect delays and should consider avoiding westbound travel on the M4 at this location and using an alternative route.”