Die Mannschaft have the chance to reach their first final since 2002 on Tuesday when they play hosts Brazil in Belo Horizonte.
While admitting that the Germans have not played to their full potential so far at the tournament, Hamann is confident that they can beat Brazil.
"They can always play better but they dealt with the pressure well against Ghana and Algeria and dominated the match for 90 minutes against France, who had perhaps been the best team at the tournament up until the quarter-finals," he told FIFA.com.
"Germany aren't at 100% just yet but Brazil haven't been either. Germany are well prepared and have no reason to fear Brazil."
Hamann scored five goals in 59 appearances for Germany before announcing his international retirement in 2005.