Australian carrier Qantas Airways said on Monday it was investigating after an Airbus jet carrying 254 passengers suffered an engine problem over Perth.
In the incident late Sunday, the twin-engined A330, which had flown from Sydney, experienced "an engine control system fault", the airline said.
"Engineers are currently investigating the cause," a spokeswoman for the airline said, adding that the flight landed safely and without incident.
The spokeswoman was unable to confirm reports that the flight lost some power to one engine, and was reduced to "idle power" at 3,000 feet, saying this would form part of the investigation.
Qantas is struggling with soaring fuel costs and worsening global conditions and recently warned its underlying profit before tax was expected to drop from Aus$552 million (US$583 million) last year to Aus$50-100 million.
But the airline has a strong reputation for safety, with the Australian flag-carrier never experiencing a fatal jet crash in 90 years.
In November 2010, an engine on a Qantas Airbus A380 exploded after taking off from Singapore but the plane returned safely to the city state.