The big crop was expected as a result of low frost damage in the winter and good water supplies this summer, it said.
A high oil content was also expected.
German oilseeds industry association UFOP said it was confident the large crop could be marketed.
"Because of the significant increase in demand for bio diesel on the one side and continuing demand for high-quality rapeseed edible oils on the other, the extra production can be placed in the market in the coming months," it said in a statement.
The strong rise was largely due to good yields being achieved because of favourable weather this year, UFOP said. Planted area was almost unchanged on the year.
Last year's crop suffered from both heavy frost damage and a summer drought which substantially cut yields.
One oilseeds analyst commented: "The good rapeseed crop will compensate for substantially tighter sunflower seed supplies." "German crushing mills are currently working at around full capacity and are expected to remain so in September and possibly until the end of the year."
"But there is strong demand for rapeseed oil from the food industry and bio diesel so the extra volumes are being consumed." Higher German rapeseed exports were expected because of the large crop.
"Larger volumes of rapeseed meal will also be looking for buyers in the feed market in the remaining months of this year," he added.