More than a year after an engine in a Qantas jet exploded in mid-air over Batam, forcing it to make an emergency landing at Changi Airport, the Airbus A380 superjumbo is still under repair in Singapore.

The work being carried out at SIA Engineering's hangar at the airport is almost completed and the aircraft is expected to be back in Australia by the end of March.

A Qantas spokesman in Sydney told The Straits Times the jet will be put back into commercial service once it is certified fit to fly.

All four engines have been replaced and repairs are being carried out on the structure of the plane, including its wings, he said.