ROME, Jan 23 (Reuters) - Italy will press ahead "with determination" with its plans to sell a stake in ITA Airways to Germany's Lufthansa, the economy ministry said on Tuesday after the European Commission opened an in-depth investigation into the deal.

In a statement, the ministry also said it hoped the EU antitrust regulator could deliver its verdict on the transaction before its stated deadline of June 6, ahead of the beginning of the peak summer travel season.

(Reporting by Giuseppe Fonte, writing by Alvise Armellini, editing by Giulia Segreti)