Tsipras's new party surges past PASOK to become Greece's leading opposition force

The RealPolls survey for Protagon.gr projected that the ruling conservative New Democracy would win 28.3 percent of the vote if elections were held now, with Mr. Tsipras's party, known as ELAS, on 21.4 percent — up more than 5 percentage points from May.

Railway safety campaigner Maria Karystianou's newly launched Hope for Democracy registered 11.9 percent, while PASOK, the current main opposition party, slipped to 9.9 percent.

The Communist Party, right-wing populist Greek Solution, right-wing populist Voice of Reason and left-wing populist Course of Freedom were all projected to clear parliament's 3 percent threshold.

Syriza, the party Mr. Tsipras led for more than a decade before founding ELAS, was projected to collapse to just 1.2 percent — a striking reversal for a movement that once governed Greece and led the European left's response to the eurozone debt crisis.

The nationwide telephone poll of 1,537 people was conducted June 20-22 and carries a margin of error of 2.8 percentage points.

The findings suggest Mr. Tsipras's relaunch is rapidly consolidating support that had splintered across Greece's fragmented opposition landscape, even as New Democracy retains a clear lead heading toward the next general election.