The board of Italy's highways regulator, ANAS, has decided to sue highway operator Autostrade for failing to make $2.7 billion in investments stipulated by its tollways license.
ANAS said it could be awarded "an order for the completion of the investment or a refund for damage inflicted," if a judge rules against Autostrade.
The decision late Friday is another hurdle in Autostrade's troubled plan to merge with Spanish highways operator Abertis Infraestructuras.
The $33.2 billion deal between Abertis and Autostrade agreed to in April would create the world's largest highway company operating in 16 countries with a road network of 4,173 miles.
Autostrade CEO Gian Maria Gros-Pietro criticized ANAS' decision in a newspaper interview published Sunday.
"We can't deny that this merger plan is unpopular with certain institutions, and for that reason it's hard to believe that the merger will actually take place," he told Corriere della Sera daily.
He added, however, that "there is no doubt the investments are late, and there's no doubt that it's not our fault."
The government has opposed the deal and is seeking to secure investment guarantees for Italy's roads network before agreeing to transfer licenses to operate the country's toll roads to Autostrade-Abertis after the merger.
Autostrade shareholders will meet Wednesday to vote on a proposed one-off dividend payment worth $2.8 billion associated with the terms of the Abertis merger agreement.
"If authorization hasn't arrived by then or if ANAS' opinion is negative, it's inevitable that we will give up on the project," Gros-Pietro said.