Proposals submitted by Atlantia's motorway unit to solve an impasse over its toll-road concession have so far proved inadequate and more work is needed on the issue, an Italian minister said on Tuesday.

The infrastructure group and the government are locked in a long-running dispute over the concession that Atlantia's Autostrade per l'Italia (ASPI) unit holds to run a large part of the country's motorways.

A solution is needed for ASPI to be able to tap a 1.25 billion euro state guaranteed the company has requested under emergency measures to face the coronavirus crisis.

"ASPI has made several proposals in the past and we've said they were not sufficient. In the coming days we'll provide an answer also to the latest ones. We need a bit of time," Transport Minister Paola De Micheli told state television.

She added ASPI had not formally communicated to the ministry the decision to slow down a multi-billion euro investment plan.

(Reporting by Elvira Pollina, writing by Giulia Segreti; editing by Valentina Za)