The move will bring to 328 the number of "Leopard 2" tanks the German army has at its disposal, up from 225 at present, a ministry spokesman told AFP, confirming a report in the weekly magazine Der Spiegel.
The tanks will have to be updated to integrate the latest technology, with the modernisation process due to start in 2017.
The decision follows the creation of a new "spearhead" force of about 5,000 troops able to deploy anywhere within a couple of days.