Another Qantas Airways' international flight was forced to turn back minutes after its take off but inherent engine trouble nor electricity issue were neither the cause this time.

Qantas said on Wednesday that QF64 from Johannesburg in South Africa and en route to Sydney was forced to return on its point of origin when birds apparently hit one of the engines of Boeing 747 that the flight was utilising.

A Qantas spokesman told AAP that the incident occurred at around 6PM Tuesday in Johannesburg and the plane's flight crew immediately swung into procedures for such scenario and successfully landed the aircraft into the South African capital.

All 171 passengers that originally boarded QF64 have been accounted for, according to Qantas, and they were given hotel accommodation from which they would wait for the next flight available going to Sydney.

The Qantas spokesman said that affected passengers could opt to take the Sydney-bound flight this afternoon or they could board a South African Airways flight set to fly to Perth at 4PM local time.

Qantas has an existing code-sharing agreement with the South African airline for its Johannesburg to Perth service route.

Also, the stranded passengers could wait out for the repair of the original plane's engine, which was slightly damage due to the bird strike, but would be operational and ready to fly again by 10:30PM local time, at the earliest.

The incident happened amidst the ongoing engine woes of a number of Qantas flights for the past two weeks and most notably of them was the engine blowout suffered by an A380 that forced the aircraft for return manoeuvre into Singapore's Changi Airport.

Following that and some more engine troubles, Qantas had announced the grounding of its entire fleet of A380 superjumbos pending the outcome of the investigation being undertaken by Rolls Royce, which manufactures the Trent 900 engines that power the aircraft.

This time, however, Qantas is insisting that the latest incident is not in league with its present engine troubles on A380s as QF64 uses a Boeing aircraft, with the national carrier blaming sheer bad luck as the cause of the problem.

Qantas maintained that bird strikes were uncommon and the airline itself admits encountering such incidents at most four times each year.