The government is seeking the return of a system that rewards the winning party with bonus seats in the 300-member parliament — a system designed to avoid coalitions. To take immediate effect, the bill must be approved with at least 200 votes but the government has only secured the support of 168 lawmakers, so the new system would be implemented only after the next election.
The vote in parliament is scheduled to take place later Friday. Prime Minister Kyriakos Mitsotakis' conservative New Democracy won general elections in July and formed Greece's first one-party government in a decade.
He has argued that governments free of coalition commitments are better placed to help Greece recover from its major economic crisis. But left-wing and center-left opposition parties maintain that coalitions are more likely to avoid the corrupt practices, exorbitant public borrowing and spending excesses that were among the lead causes of the financial crisis.
Greece ended its third successive international bailout in 2018 after losing market access in 2010.