A Qantas Boeing 747 returned to Singapore with an engine problem shortly after takeoff on Friday, local TV stations reported.
Channel 5 and Channel News Asia stations did not give details of the problem, except to say that flight QF6 to Sydney suffered a problem with engine one and had to come back. A 747 has four engines.
More details were not immediately available.
On Thursday, an Airbus A380 superjumbo jet belonging to the Australian airline made an emergency landing in Singapore after one of its four engines suffered a blowout. That aircraft was also going to Sydney.
Qantas grounded its fleet of A380s and other airlines made checks of their planes that have the same Rolls-Royce engine. The A380 shed debris from the busted engine onto the thickly populated Indonesian island of Batam.