Unidentified vandals smashed the offices in Hania, Crete, of the self-proclaimed multi-billionaire and fugitive Artemis Sorras.
According to local reports, the assailants smashed the office's glass façade and also vandalized the interior.
Members of Sorras's political movement, the ultranationalist Convention of Greeks, claimed that the offices were targeted due to its support of Sunday's "Macedonia" protest rally in Athens.
They claimed that the movement's offices in other parts of the country were also targeted.
Sorras spent years encouraging austerity-weary Greeks not to pay their debts before shifting stance early this year and posting a video online calling on his supporters to pay up to avoid losing their homes.
Prior to his chane of heart, Sorras had claimed to have enough money to pay off Greece's entire public debt and had encouraged thousands of followers to tell their tax offices that their dues would be paid off by a 600-billion-euro bond he claimed to hold.
Last March, Sorras and his wife were convicted to eight years in jail for embezzlement. In December, a court on Crete started hearing a trial against Sorras and eight others on charges of distributing false information and inciting civil disobedience.