A driver has been lucky to escape uninjured after a bus crashed into at least five parked cars at Northmead in Sydney's west today.

Fire and rescue crews were alerted to the crash on Boundary Road near Kleins Street in Northmead at around 2.45pm.

The driver was not injured. (9NEWS)

Images from the scene showed the yellow bus resting on top of an upturned 4WD.

Paramedics assessed the driver, aged in his 50s, who did not require further treatment but was taken to Westmead Hospital for assessment.

The bus driver was taken to Westmead Hospital for assessment. (9NEWS)

A spokesperson from NSW Ambulance said no one else was injured and the parked cars were empty at the time.

It's believed no one else was on the bus at the time.

Motorists are advised to avoid the area as delays are expected.

The cars were parked at the time. (Supplied)