The leader of Greece's far-right Golden Dawn party was sent to prison on Thursday (October 3) pending trial on charges of belonging to a criminal group, making him the first elected party chief to be jailed in decades.

Golden Dawn leader Nikolaos Mihaloliakos appeared before investigating magistrates and a prosecutor during a six-hour plea session to respond to charges of founding and participating in a criminal organisation.

Mihaloliakos has denied the charges against him. He was arrested on Saturday (September 28) alongside other party members as part of the government's efforts to rein in a party it says is a neo-Nazi criminal gang.

On Wednesday (October 2) three senior Golden Dawn lawmakers were freed pending trial on the same charges in an unexpected setback to the government's efforts to clamp down on the party.

Golden Dawn rose from being a fringe party with an anti-immigrant platform to win 18 seats in parliament in last year's election. It has drawn on anger over the debt crisis, budget cuts, high unemployment and corruption to become what opinion polls indicate is Greece's third most popular party.

But the latest polls show it has lost about a third of its support since the killing.

Another senior Golden Dawn lawmaker, deputy leader Christos Pappas, will face the magistrates later on Thursday to respond to the charges.