Drivers are being urged to avoid the M1 Pacific Motorway north of Sydney after a road worker was struck by a ute, with 11 kilometre traffic queues for drivers heading into the city.

The worker was hit at Berowra just after 3am on Wednesday forcing the closure of the motorway linking Sydney and the Central Coast.

Just before 7am the motorway was opened to southbound drivers, with cars being diverted onto the northbound lanes.

All northbound traffic was being diverted onto the Pacific Highway at the Windybanks Interchange.

Southbound traffic is queued for 11km, and northbound traffic on the Pacific Highway is banked back 5km.

“Motorists should allow plenty of extra time, expect delays, reduce speed and exercise caution,” the Transport Management Centre said in a statement.

“Anyone needing to travel between the Central Coast and Sydney, including HSC students, should consider catching a Central Coast & Newcastle Line train instead.”

-AAP