Eastern civil rights activists said new evidence proved that Mr Gysi, a lawyer who played the key role in returning the Party of Democratic Socialism (PDS) to parliament in last week's election, informed on dissidents to the Stasi.
The PDS denied the allegations, but Gerd Poppe, the former dissident and now Greens politician, demanded that Mr Gysi step down as PDS parliamentary leader in the new assembly.
Mr Gysi, who has denied the allegations, has revived the PDS by attracting young voters. He is a key moderator between party reformers and a rival faction of old-guard functionaries. ReuterReuse content