UPDATE: A Rex spokeswoman said the plane forced to turn around during a flight from Sydney to Albury had "experienced a cockpit indication" about 20 minutes into the flight.
"As a precautionary measure, the pilots elected to return to Sydney with the flight landing normally at 7.05 pm," the spokeswoman said.
"To ensure that passengers were re-accommodated Rex deployed a spare aircraft and crew, with ZL783 re-departing Sydney at 8:49 pm."
The airline did not elaborate on what the indication involved.
EARLIER: A plane between Sydney and Albury has been forced to turn around during the journey and return to Sydney.
The 6.25pm Regional Express flight took off as scheduled from Sydney on Wednesday night.
Data shows the flight turned around near Marulan and returned to Sydney airport, and landed at 7.08pm.
The flight, which involved a Saab 340 twin-turboprop aircraft, had been scheduled to take 75 minutes but lasted 54 minutes, and travelled 296 kilometres of a planned 459 kilometres.
It's unclear what caused the incident, but an image shows firefighters near the plane at the airport.
Rex has been contacted for comment.