Parliament president Norbert Lammert said in a statement that a special body made up of MPs and other dignitaries would meet to elect a new president to replace Christian Wulff who resigned on Friday amid allegations of corruption.
March 18 is the last possible date for the body to meet, as it must convene at least 30 days after the resignation of a president.
Gauck, 72, is certain to be elected as he enjoys the support of all the main parties in the body, with the exception of the far-left Linke.
Wulff was forced to resign on Friday after prosecutors called for his immunity to be lifted so they could investigate allegations that he enjoyed favours from a film producer friend.
Wulff, the handpicked choice of Angela Merkel, won a 2010 election over the popular Gauck but the vote turned into a debacle for the chancellor as members of her own party defied her wishes and voted against Wulff.