Greece is trying to change the conditions of a deal to lease 14 regional airports to a joint venture led by German airport operator Fraport, a source familiar with the matter told Reuters.
The deal, worth 1.2 billion euros ($1.3 billion), was agreed in 2014 but has been hit by turmoil caused by the election of the new leftist-led, anti-austerity government in January.
The Greek government now wants a stake in the consortium, which also includes Greek energy firm Copelouzos, and wants to cut the number of airports in the deal to seven, the person said on Thursday.
Fraport would be willing to consider a limited amount of state involvement, but only if the conditions could be agreed by all sides, the source said, adding Fraport boss Stefan Schulte met with Greek representatives this week
Fraport said there had been constructive talks with Greek government representatives on the sale but declined to provide details.
It has previously said it expects the deal to conclude by the end of 2015 or the beginning of 2016, a slippage from its earlier timetable of the third quarter of 2015.