Lawyers representing Greece's extreme right-wing Golden Dawn party are demanding a change of venue for security reasons in the trial of party leaders and members, after their clients were threatened by suspected members of a leftist group being led to another courtroom for a separate trial.

Golden Dawn leader Nikos Michaloliakos and party lawmakers are among 69 defendants accused of running a criminal organization in the closely watched case held in a special courtroom in the country's largest prison, Korydallos.

A separate case against suspected members of the left-wing Nucleii of Fire group, which is accused of several bombings, is also being heard there.

Nucleii suspects heading to their own courtroom Friday managed to open the Golden Dawn courtroom door and threaten the defendants, throwing a bottle before police intervened.