The next election will be contested under a different system after leading parties failed to form a coalition.
Newly elected Greek lawmakers were sworn in Sunday but the Parliament in which they sit may be dissolved as early as Monday, ahead of fresh elections on June 25.
No party achieved an overall majority in the election on May 21, which was held under the simple proportional representation voting system.
The ruling New Democracy Party which secured 40.79% of the vote, won 146 seats, five short of an overall majority in the 300-member chamber. The main opposition Syriza, with 20.07% - almost 11.5 points lower than in the previous election – won 71. The socialist PASOK was third.
Elected representatives failed to form a coalition and the leaders of the three main parties, including Prime Minister Kyriakos Mitsotakis, also the leader of the ND party, returned their mandates, to form a government almost as soon as they got them.
A constitutionally mandated meeting on Wednesday with President Katerina Sakellaropoulou and all five leaders of the parties represented in parliament merely confirmed that a second election would take place.
A caretaker government headed by a senior judge, Ioannis Sarmas, was sworn in on Thursday.
The next election will be contested under a different system. The lawmakers will elect the speaker and deputy speakers Monday morning. Parliament will be dissolved either Monday or Tuesday, signalling the start of the electoral campaign. A bonus of 25-50 seats will also be awarded to the winning party, depending on its performance.
Although New Democracy is the clear favourite, an overall majority is by no means automatic: the more parties there are in Parliament, the higher the share of the vote needed for an outright majority will be.
On May 21, two more parties barely missed the 3% threshold for gaining parliamentary representation. If they get in on June 25, this could raise the score required for the election winner to achieve an overall majority to about 39%.
New Democracy officials appealed to voters not to take the result for granted and abstain while opposition leaders called on the people to clip New Democracy’s wings and avoid the prospect of an all-powerful conservative government.