All three of Qantas's much-hyped A380 aircraft have been grounded over the past four days due to recurring problems with the plane's fuel tank systems.
Qantas was forced to declare one of the aircraft "unserviceable" last night, after scores of passengers had waited more than 12 hours for a fuel leak to be repaired.
It has now emerged that the airline's other two A380 are grounded at Sydney airport after experiencing similar problems.
One is due to return to service at 5.40pm tonight and the other tomorrow.
The airline's flagship, the Nancy-Bird Walton, was delayed in Sydney for 19 hours on Saturday, before eventually being cleared to fly to London.
However, on arrival at Heathrow airport it was again found to be leaking fuel and experienced a nose wheel ground steering issue, being declared unserviceable.
A Qantas spokeswoman said it was natural to expect "the accessional shake down" with a new aircraft and the airline was working with airbus to resolve the issues.
"Our engineers are currently working to resolve the issue and we hope to have the aircraft return to service very soon," the spokeswoman said.
"We are working very closely with airbus, but we remain committed to the A380, as the cornerstone of our new generation. We apologise to our customers."