Defence Minister Rudulf Scharping has insisted on keeping the military draft which was imposed when Germany recreated its armed forces in 1955 - a decade after the defeat in World War II.
The idea was to create soldiers who were "citizens in uniform" in a bid to break away from the professional officer class which had previously dominated Germany's armed forces.
But the Greens Party, which serves as German Chancellor Gerhard Schroeder's junior coalition partner, are demanding an immediate end to the draft and the issue has become one of several policy differences which are shaking the centre-left government.
Germany has also come under pressure to modernise its armed forces as allies such as France have dumped conscription for a professional military.
Rau told officers at an army reform conference in Leipzig that the "citizen in uniform" concept remained one of the Bundeswehr's key pillars.
"As the first German army of conscription the Bundeswehr is firmly anchored in parliamentary democracy," said Rau.
The Schroeder government earlier this year approved the biggest set of reforms in the 45-year history of the Bundeswehr.
Troop strength will be cut to 282,000 by 2004, down from the current target level of about 340,000. The number of conscripts will sink from the present 135,000 to 77,000.
In order to boost rapid deployment capacity the Bundeswehr will triple the number of elite, crisis reaction troops to about 150,000. New heavy airlift planes, the Airbus A400M, have been ordered to allow global projection of force for military and humanitarian purposes.
Rau criticized that fact that armed forces were being used for civilian projects in places such as the Balkans.
"Drilling wells, operating hospitals or replacing administration and police structures is really not the purpose of an army," said Rau.
Civil and police units for such tasks needed to be built up instead of always just sending in the Bundeswehr, he said
(la/dpa)