ENAGÁS, S.A. Greece relaunched the sale last year as part of its latest 86 billion euro international bailout, and after a previous 400 million euro (£350.7 million) deal with Azerbaijan's SOCAR fell through in 2016.
Last month Greece received two binding bids from Italy's Snam, Spain's Enagas Internacional and Belgium's Fluxys, and from a consortium of Spain's Regasificadora del Noroeste (Reganosa), Romania's Transgaz and the European Bank for Reconstruction and Development (EBRD).
The privatisation agency said in a statement that it asked the bidders to improve their financial offers.
"Τhe prices offered exceeded 400 million euros," Energy Minister George Stathakis said in a press release. He added the new round with improved bids will be completed in a few weeks.
Snam declined to comment, while Reganosa did not immediately respond.
Athens is selling a 31 percent stake and Hellenic Petroleum, Greece's biggest oil refiner, its 35 percent stake in the grid.
A share purchase agreement and a shareholders' agreement for DESFA are due to be signed by April for the sale to conclude by June, before Greece exits its third bailout in August.
DESFA, which owns and operates Greece's natural gas network and a liquefied natural gas terminal on an islet off Athens, is considered a valuable asset as gas consumption in Greece rises and the country seeks to boost its presence in the regional energy market.
DESFA transports gas from the Greek-Bulgarian and Greek-Turkish borders to Greek consumers via a 1,459-km (907-mile) pipeline.
(Reporting by Angeliki Koutantou, Lefteris Papadimas, additional reporting by Stephen Jewkes in Milan; editing by Elaine Hardcastle and Alexandra Hudson)
