Opinion polls published on the final day of campaigning in Greece suggest the left-wing Syriza party and conservative New Democracy are in a dead heat before a general election Sunday.

Three surveys published Friday show the two parties roughly level within the margin of error, with the winner likely to require the support of two smaller parties to form a coalition government.

Syriza leader Alexis Tsipras resigned as prime minister and called the snap election last month after reaching an agreement with eurozone creditors for a third bailout that triggered a split within his party.

Syriza has maintained a narrow lead in most polls, and has ruled out forming a grand coalition with the conservatives.

Under Greece's electoral system, the first party receives a 50-seat bonus in the 300-member parliament.