Germany's defence ministry said last week there were signals from European defence equipment agency OCCAR, which is negotiating with Airbus on behalf of governments seeking to buy the planes, that deliveries could be delayed further.

A total of 170 of the planes have been ordered by seven partner nations, which also include Belgium, Britain, France, Luxembourg, Spain and Turkey.

Jean-Marc Nasr, responsible for Europe, the Middle East and Africa at Airbus Defence and Space, told a news conference that there had been difficulties in the organisation of the supply chain.

"We would like to optimise this system," he said, adding that there was "no problem with the fuselage as such".

Germany's federal armed forces took delivery in December of the first of a total of 53 ordered A400M aircraft, with another five due to be handed over this year.

France already has six in use and hopes to receive a further four this year. A spokesman for the French defence ministry was not aware of any delays.

An official from Turkey's Undersecretariat for Defence Industries said on Monday it had received two A400Ms in 2014 but the delivery of these had been delayed. Turkey is due to receive two more in 2015 but the official said delays on these were also expected.

A British Ministry of Defence representative said on Monday it was up to Airbus to deal with any delivery problems, but added he was not aware of any issues with the project in the UK.

Nasr added that he "very much hoped" to sign export contracts for the aircraft this year. He told Reuters five to 10 countries had already signalled their interest and that several negotiations were well advanced.

So far, Malaysia is the only export buyer, having ordered four of the airlifters.

(Reporting by Cyril Altmeyer; Writing by James Regan; Editing by Andrew Callus)