Police said emergency services were called to the crash on King Edward St, Kensington, at 3.30am.
"A car caught fire after colliding with a truck," police said.
"Two occupants of the car died at the scene."
The driver of the car has serious injuries and the driver of the truck has moderate injuries, police said.
"Both were transported to hospital."
The Serious Crash Unit was notified and the circumstances of the crash are being investigated.