The official, Hans-Peter Bartels of the governing Social Democrats, told the Berliner Zeitung newspaper that the factions in parliament had agreed that 1.142 billion euros (1.443 billion dollars) could be spent on the project.
He said Germany would order between 12 and 24 of the MEADS (Medium Extended Air Defense System) units, which can be used to shoot down other missiles or aircraft and have a range of around 1,000 kilometres (620 miles).
The ground-to-air system, which has already been under development for several years, is designed to replace the Patriot missile system in the United States and Germany and Italy's Nike Hercules system.
The project is a joint venture between Lockheed Martin Corp, the European Aeronautic Defence and Space Company (EADS), MBDA-Italia and Lenkflugkorpersysteme (LFK) in Germany.
According to Lockheed Martin, it is currently financed 58 percent by the United States and 25 percent by Germany, with Italy funding 17 percent.
The system is not linked to the proposed US anti-nuclear missile shield.
Germany has recently tightened defence spending and is streamlining its military, and the costly MEADS project has been the subject of protracted parliamentary debate.