The Greek government’s sale of its 33 per cent stake in OPAP could hit a problem as two potential buyers have filed complaints alleging the sale process has not been transparent.

Emma Delta and a consortium led by Gauselmann and Playtech said they will sue if necessary. The stake is estimated to be worth €660m. They are among eight companies expressing interest in the sale. Others include Intralot, TPG Capital and a unit of the Chinese conglomerate Fosun.