Immigrants take part in a peaceful protest against alleged police harassment in central Athens (AP)

Greece's Supreme Court has cleared the extreme right Golden Dawn party to contest the May 25 election to the European Parliament, despite it being prosecuted by authorities as a "criminal organisation".

The court approved a list of 43 parties that will contest the poll. Governing partner New Democracy and main opposition Radical Left Coalition, also known by its acronym, SYRIZA, are vying for first place.

Golden Dawn, running on an anti-immigrant, nationalist platform, is variously shown as third or fourth in polls.

Golden Dawn's leader and his deputy have been behind bars since last autumn and have been followed recently by several more politicians, while awaiting trial.

They are accused of taking part in criminal acts, including murder, arson and extortion. Prosecutors have labelled the party a military-style criminal organisation.