The aircraft suffered a severe tailstrike during rotation and is reported to have struck antennae on the ground just beyond the runway end.
Emirates says the aircraft, an A340-500 (A6-ERG) operating flight EK 407 from Melbourne to Dubai, "had to return to Melbourne shortly after take-off when a flight deck indication alerted the captain to the possibility of the tail contacting the runway on departure".
The aircraft climbed safely to an intermediate altitude and contacted air traffic control to arrange the return to Melbourne. The landing was completed without incident.
Passengers among the 225 people on the aircraft report that an engine emitted flame, there was a bang, and smoke entered the cabin. Another of the passengers confirmed that the aircraft "took too long to take off". The crew took about 30min to dump fuel over the sea south of Melbourne and then returned to land safely.