A police operation has sparked commuter chaos in Sydney‘s west as multiple lanes on the busy M4 motorway are closed. 

All westbound and eastbound lanes of the M4 near Merrylands are closed between Burnett Street and the Cumberland Highway. 

Police were called to the motorway shortly before 5.30am following reports of a concern for welfare and set up an operation. 

Motorists have been told to avoid the area and expect delays on Friday morning. 

‘Avoid the area, use an alternative route and allow extra travel time,’ Live Traffic Sydney said on X. 

Westbound traffic is banked back about 9km to Silverwater and motorists heading to the city are bumper to bumper for about 15km to Eastern Creek. 

Drivers travelling westbound on the M4 can exit at Burnett Street, use the Great Western Highway and Cumberland Highway to rejoin the M4.

It’s understood the police operation is due to a mental health incident.  

Police have said there is no ongoing threat to the public. 

Live Traffic NSW said the delay began at 5.23am on Friday. 

Police, motorway management and Transport for NSW crews are on the scene.