BERLIN, Sept 29 - Economy Minister Wolfgang Clement said on Monday that the German economy was still in a weak state and urged opposition conservatives not to block tax and welfare reform plans in parliament. "There is a lot at stake. The situation in Germany is often underestimated. We are still in a weak economic situation and we urgently need measures to strengthen confidence," Clement told a news conference. Clement said it would be "catastrophic" if the opposition blocked economic reform plans with their majority in the Bundesrat upper house of parliament.//