SYDNEY (AFP) - Australian airline Qantas marked the official launch of its partnership with Emirates on Sunday with a spectacular tandem flyover of the Sydney Harbour Bridge by two Airbus A380s.

Qantas said the feat by the two super-jumbos - one from each of the carriers - is thought to be the first time anywhere in the world that two commercial airline A380s have flown in formation.

As the planes flew over the bridge the Qantas jet was in the lead, flying at about 450 metres.

"The sight of two of the world's great airlines flying two of the world's largest aircraft so close together over Sydney Harbour is a once-in-a-lifetime opportunity," Qantas chief pilot Philip Green said before the event.

"There has been a huge amount of planning which has been necessary to make this possible, including seeking approval from safety regulators in both Australia and the United Arab Emirates."

Pilots from both airlines have completed dozens of special simulator training sessions since January, with Emirates pilots travelling Down Under to conduct sessions in Qantas's A380 simulator in Sydney this month.

The aircraft took off from Sydney airport early Sunday, flying north along the coast, then south and slightly out to sea, before turning and cruising over the city, passing the Opera House and flying over the Harbour Bridge.

Australia's competition regulator formally approved the Qantas-Emirates tie-up last week, allowing the carriers to combine operations for an initial period of five years.

The airlines will coordinate ticket prices and schedules and struggling Qantas will shift its hub for European flights from Singapore to Dubai, ending a decades-long partnership with British Airways on the London route.