The defence ministry highlighted the “unsatisfactory readiness” of many key weapons systems in a 106-page report to parliament this week.
The criticisms come amid increasing pubic outcry about the military’s failure to deal with the issue.
The report backed up a prior parliamentary report released last week that spoke of big, persistent gaps in military equipment and personnel.
It said although 550 more weapons were available in 2017 than in 2015, readiness was improving slowly.
But the report said more time and money were required to recover from decades of slashes in spending.
Defence Minister Ursula von der Leyen told Passauer Neue Presse newspaper: “We will need significantly more funds in coming years so the Bundeswehr (armed forces) can accomplish the missions and assignments that parliament gives it.”
A new governing coalition is set to add €10billion to the military budget over the next four years if approved.
Germany made drastic military spending cuts after the end of the Cold War, but slowly boosted spendings after Russia’s annexation of Crimea in 2014.
The report mentions “quality deficiencies” that took place during maintenance for the “limited and clearly lower-than-expected” availability of the Airbus A400M military transport.
In 2017, on average just three of 15 aircrafts delivered by the end of the report period were ready for use.
Because of a “shortage of a wide variety of replacement parts” and extended maintenance periods, only 29 of 128 Eurofighter fighter jets, built by Airbus and other European arms makers, were available on average in 2017, the report said.
Although there had been enough aircrafts for air policing missions in the Baltic region and to take part in NATO missions, the shortage has constrained pilot training.
The report also said it needs to end the deployment of its NH-90 and Tiger helicopters from mid-2018 as part of a UN peacekeeping mission in Mali, as their sustainability is in danger.
The ministry said intense coordination efforts are needed to make sure sufficient Leopard 2 tanks can be continuously deployed in Lithuania under NATO’s Enhanced Forward Presence initiative, and for Germany’s rotational leadership of the Very High Readiness Joint Task Force (VJTF) in eastern Europe.