Cracks have been found on the wing ribs of at least three Airbus A380s belonging to Singapore Airlines and Qantas Airways.
Both carriers said the cracks were discovered in the second quarter of 2011, and that they have been repaired and posed no danger to flight safety.
The carriers' comments come a day after Airbus said "very small cracks" have been found on some "non-critical wing rib-skin attachments on a limited number of A380 aircraft".
Singapore Airlines said the cracks were first discovered during an A380 inspection last year.
"These pose no safety issue and repairs were carried out on the aircraft. Repairs were subsequently carried out on a second aircraft," said an SIA spokesman.
He added that the relevant authorities have been informed and checks and repairs will be done on other A380s as the aircraft undergo routine C checks. Both affected aircraft are back in operation.
Qantas meanwhile said that "minuscule cracking" was found on the wing ribs of the A380 that suffered an uncontained engine failure in November 2010. This aircraft is still in Singapore, where it made an emergency landing after the incident, and Qantas hopes it will return to service in March.
"Investigations have found that the cracking is unrelated to the engine failure incident experienced by this aircraft in November 2010 and is not unique to Qantas. It has now been repaired," said a Qantas Spokesman.
Airbus said that it has since developed an inspection and repair procedure which will be done during routine, scheduled four year maintenance checks for the A380s. It has informed all A380 operators and the European airworthiness authority is aware of the issue and has accepeted its recovery approach, said a spokesman.
"This is not a safety issue and aircraft performance is not affected. Any fix, if necessary, can be done during regular maintenance," Airbus added.