A Golden Dawn statement Thursday said triple jumper Voula Papachristou's punishment was a display of inverted racism.
It says the Hellenic Olympic Committee's decision shows how the Greek "system ... literally exterminates, for paltry reasons, whoever dares to express a different opinion, even in jest."
After years in the margins of Greek politics, Golden Dawn won nearly seven per cent of the vote in parliamentary elections last month, and elected 18 lawmakers in the 300-seat Parliament.
Greece's Olympic committee expelled Papachristou Wednesday for "statements contrary to the values and ideas of the Olympic movement."
The 23-year-old athlete has apologized for her comments.