Main opposition New Democracy has indicated that it will support an amendment that divides up the large 2nd Athens and Region of Attica electoral constituencies, with ND leader Kyriakos Mitsotakis due to inform parliament when he addresses the plenum on Thursday afternoon, sources said.
The amendment is attached to a draft bill for the "Kleisthenes" plan on reforming local government.
According to the sources, Mitsotakis has already asked the MPs in the party to indicate which area they would prefer to stand in, though final decisions will be made at a central level.
With ND's support for the measure, it is expected to reach the required 200 votes in parliament that will allow its implementation in the next elections.
The main opposition is also expected to insist on supporting an amendment to grant Greeks living abroad the option to vote in general elections from their country of residence, through embassies and consulates.