Italian railway infrastructure manager RFI suspends contract with private company blamed for bringing Rome's rail network to its knees.

Italy's transport minister Matteo Salvini on Wednesday blamed a private company for causing the power outage that resulted in train chaos in Rome and across the country earlier that day.

Commuters and tourists faced delays of up to four hours after a blackout between Termini and Tiburtina railway stations paralysed the capital's rail network and led to the cancellation of more than 100 trains.

The delays affected regional trains across the Lazio region, including to Rome's Fiumicino airport, as well as high-speed services to Milan, Naples and Turin, leaving thousands of people stranded.

Salvini told reporters on Wednesday afternoon that the blackout had been caused by a worker from a private firm hammering "a nail into a cable" at "three o'clock in the morning".

"It is not possible that a mistake by a private company can stop half of Italy", Salvini said, adding that he wanted "the name, surname and tax code of the person who ruined the day for thousands of Italians who were stranded from north to south."

Salvini, who earlier on Wednesday faced calls from the opposition to resign, came in for renewed criticism for his explanation about how the capital's rail system was brought to its knees, amid claims that he used the private firm as a scapegoat.

On Wednesday evening, the Italian railway infrastructure manager RFI said it had suspended the contract with the company in question.