European aerospace group Airbus has denied that its A380 superjumbo aircraft programme is in trouble, after airlines warned they faced further delays on delivery of the aircraft.

Dubai's Emirates airline, the biggest A380 customer, and Abu Dhabi-based Etihad Airways, both said they had received warnings of delivery delays on the world's largest passenger airliner, which is already two years behind schedule.

Airbus confirmed that chief executive Tom Enders had written to all A380 customers telling them production had reached a critical phase. It announced a "major review" of A380 production last week, but insisted this was a normal procedure for this stage of the programme.

Emirates, the largest Arab carrier, hopes to receive five A380s before the end of March 2009 and another 12 in the year to March 31, 2010. Etihad has ordered four of the $300 million, 525-seat planes.

Europe's biggest single industrial project first faced upheaval in 2006, when A380 sections reached the French assembly plant with wiring flaws that caused production to halt.

Image: The A380 could be delayed again