According to a statement published on ADEDY's website, several demonstrations will be held in the city center to mark the one-year anniversary of the referendum in which 61.3 percent of voters rejected the creditors' proposal that the Greek government later signed up to.
The union reportedly reproached the Greek government for pursuing austerity measures that hurt regular people.
Athens signed a deal with its creditors, which include the International Monetary Fund (IMF), the European Central Bank (ECB) and eurozone nations, in the summer of 2015 for a third bailout package worth about 86 billion euros ($96 billion) in exchange for highly unpopular austerity reforms such as pension cuts and tax hikes.
Under two previous bailout programs, the last of which expired on June 30, 2015, Greece received about $270 billion from the IMF, the ECB and eurozone countries. Those loans were also conditional to the implementation of austerity measures.