Abertis, which owns 90 percent of French motorway operator Sanef, said in January it would invest 147 million euros in an investment plan put forward by the French transport ministry.

"We have identified potential investment needs relating to our network and are working on a number of proposals that represent a total of close to 4 billion euros," CEO Francisco Reynes told French newspaper Les Echos.

Reynes said the investments would be in exchange for "reasonable consideration," with the most preferable option being an extension to the concessions granted to motorway operators.

The investments would be concentrated in the region of Ile-de-France, he said.

(Reporting by Gwénaëlle Barzic; Writing by Angus Berwick; Editing by Louise Heavens)