Greek Prime Minister Alexis Tsipras' leftist SYRIZA will be the biggest party after elections on Sept. 20, but most voters think he was wrong to seek a fresh mandate, according to the first major opinion poll published since he resigned last week.
SYRIZA was supported by 23 percent of those polled, with the conservative New Democracy party second on 19.5 percent, according to the survey, carried out by pollsters ProRata and published in Friday's Efimerida Ton Syntakton newspaper.
The previous ProRata poll in early July showed a wider gap in Syriza's favour, putting the party on 26 percent compared with 15 percent for New Democracy.
Popular Unity, the party formed last week by disaffected Syriza members who oppose the country's latest 86 billion euro bailout, was backed by 3.5 percent in Friday's poll – just above the 3 percent threshold needed to enter parliament.
Independent Greeks, the ally in Tsipras' former coalition government, scored 2 percent.
Based on the survey, 64 percent of Greeks believe Tsipras's move to seek a fresh mandate through snap polls was wrong, while 68 percent agree that Greece must stay in the eurozone at any cost, even if that meant further austerity.
"The answers to these two questions lead to the conclusion that early elections may cost the (former) prime minister and SYRIZA," the newspaper said.
One third of those who supported Tsipras' party in the January 2015 elections that took him into office said they were unsure if they will do so again, the paper said.
The poll also showed 25.5 percent of voters were still undecided, making them the biggest bloc.