Experts estimate the yearly operating costs would reach 5.9 million euros (5.26 million dollars) per aircraft, at least double the cost of the current Franco-German Transall C160, the auditors said in a report cited by the conservative newspaper.

The institution therefore asked Chancellor Gerhard Schroeder's centre-left government to reexamine the order and significantly reduce the number of planes requested, Die Welt said.

Berlin initially ordered 73 A400M planes but it announced in December that it was paring back its order to 60 as a result of Germany's flagging economy and the poor state of public finances.

The audit office also criticised Defence Minister Peter Struck's intention to pre-finance the A400M with outside financing, a move that would add 680 million euros to the overall price tag, the newspaper said.

In order to save money, auditors advised the government to delay its planned purchase of Eurofighter aircraft -- single-seater, twin-engine fighter planes being built by a pan-European consortium -- which would allow the state to finance the A400M planes itself.

The A400M project is viewed as a crucial component of efforts by the European Union to strengthen its military capability and coordination. The first aircraft are expected to be delivered in 2008.

Germany's participation in the Airbus project is critical and even its reduced order of 60 is still the biggest of the eight nations involved.

A total of 196 planes, with four turbo-prop engines, were orginally ordered: 73 by Germany, 50 by France, 27 for Spain, 25 go to Britain, 10 to Turkey, seven to Belgium, three to Portugal and one for Luxembourg.

The final amount was reduced to 180 after Portugal pulled out of the project and Berlin reduced its order to 60 aircraft.

Germany's partners within the European Union and NATO have long called on Europe's biggest economy to commit more of its resources to defence spending.

But the country is struggling to meet euro-zone requirements to keep the public deficit below three-percent of gross domestic product in 2003 after exceeding the limit last year.

SPACE.WIRE