Greek socialist party PASOK is holding a two-day congress in central Athens on Tuesday and Wednesday to mark the 39th anniversary since its founding on September 3, 1974.

The event, which will be hosted at the Hellenic Cosmos venue in the southern suburb of Tavros, is titled "From the 'metapolitefsi' to the crisis: From the crisis to reformation: PASOK and Greece, 1974-2014."

The symposium will address the history of the Panhellenic Socialist Movement founded by the late Andreas Papandreou in the aftermath of the 1967-1974 military junta, as well as its future goals and objectives.

PASOK, the junior partner in Greece's two-party coalition government, has seen its popularity drop from over 40 percent to 13.8 percent in national elections in July last year.

The party governed Greece from 1981-1989 under Papandreou, from 1996-2004 under Costas Simitis and from 2009-2012 under Andreas Papandreou's son, George Papandreou, who signed Greece's first bailout deal with international lenders.

Party leader Evangelos Venizelos will deliver the keynote speech at the gathering.

Simitis and George Papandreou will also speak.