ATHENS (AFP) - Greece's anti-austerity leftist party Syriza held a slight lead in European Parliament elections, exit polls showed on Sunday.

Syriza was ahead by about three points over the leading government party, conservative New Democracy, polls jointly carried out by six leading opinion companies showed.

Syriza have between 26 and 30 per cent while New Democracy have between 23 and 27 per cent, the polls showed.

Neo-Nazi party Golden Dawn ranks third with up to 10 per cent of the vote, despite an ongoing criminal investigation and the fact that several of its leading members are in pre-trial detention.

The other party in the government coalition, the Pasok socialists, are fourth with up to nine per cent.

The polls also show that in the second round of local elections, held alongside the EU ballot on Sunday, Syriza's candidate is in a close race to win the governorship of the greater Athens area.

Syriza's 39-year-old leader Alexis Tsipras, a candidate to head the European Commission for the European Left, has called the vote a "referendum" on austerity.

In contrast, Prime Minister and New Democracy leader Antonis Samaras has warned that a Syriza victory could destabilise Greece's fragile recovery.