The eight found Monday were confiscated by authorities who located them at the Greek Post Office's distribution center in Kryoneri, Athens, police said.
A security source told Reuters they were "addressed to officials at economic institutions and companies" at various European countries but would not be more specific.
Last week, a mail bomb sent to the IMF's offices in Paris exploded and injured a secretary.
"We sent parcel bomb to the German finance minister as part of the second act of the Project Nemesis campaign".
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The explosion, meant for the IMF's European representative, Jeffrey Franks, had also been sent under a false name from Greece and triggered a crackdown by the Hellenic Police.
The find comes after a book concealing explosives was intercepted by German authorities on 15 March before reaching its intended recipient - German finance minister Wolfgang Schaeuble.
The eight parcel bombs, falsely labelled as being sent by academic institutions, were found and defused on Monday. The country's finances have been under strict supervision by European institutions and the International Monetary Fund.
The anti-terrorist services reckon that the action was carried out by anarchists from the organisation Conspiracy of Fire Cells. The group initially carried out arson attacks but turned to bombings in 2009.