Italy's government has asked a commission to carry out a cost-benefit analysis to decide whether to complete the rail link, a project that has divided the ruling coalition.
"It's hard to demonstrate that the work does not stand," Garavaglia told the newspaper.
He also said the government is considering using state lender Cassa Depositi e Prestiti (CDP) in its privatisation drive for this year, saying it would be the only way to sell assets "without depressing companies' market prices".
Italy plans to raise 11 billion euros (£9.5 billion) this year through the sale of assets.
(Reporting by Giulio Piovaccari; editing by Darren Schuettler)
