Five cars caught in Sydney inferno

Four cars have been destroyed and another damaged after a suspected arson attack in Sydney's exclusive inner-east.

Investigators believe a Mercedez Benz 4WD parked in the driveway of a Bellevue Hill home was torched shortly before 5am on Monday.

Only one of four cars engulfed by flames when the inferno spread along Birriga Road is salvageable, police say.