Former German Chancellor Gerhard Schroeder said Thursday China and Germany must increase the number of Sino-German joint ventures following the fast expansion in bilateral trade.

He made the remarks at the on-going 2010 China International Forum on New Energy & Sino-German Cooperation Summit being held in Qingdao City, in east China's Shandong Province, from April 28 to 30.

"Economic involvement must be intensified. Following a quick expansion in trade, steps must be made to increase the number of joint ventures," he said.

"Germany should not take a defensive approach to Chinese investment in the German economy," as "investment and openness were the elements that drive our economy forward," he said.

He said "China is the most important trading and investment partner for Germany."

Sino-German trade totalled 91.9 billion euros (121.5 billion U.S. dollars ) in 2009 despite the global financial crisis, according to German statistics.