The Airbus A380 was travelling from Dubai when the problem was detected, forcing an unscheduled landing in Perth shortly before 3:00 AM.
"While travelling to Sydney from Dubai, the pilots received an indication that there was a technical issue with the aircraft so they diverted to Perth to have the issue repaired," the airline said in a statement.
Engineers were examining the plane, which landed safely, and it was scheduled to leave Perth for Sydney later today, added Qantas.