ROME: Italian President Giorgio Napolitano on Sunday voiced "regret" over last month's cruise ship disaster off Tuscany that claimed 32 lives.

"It was a tragedy and I express my regret for whatever responsibility there was for Italy and for Italians," Napolitano said after a special remembrance mass in a Rome basilica celebrated by the head of the Catholic Church in Italy, Cardinal Angelo Bagnasco.

"I reaffirm my affectionate solidarity with the relatives of the victims afflicted by many days of anxiety," the 86-year-old Napolitano said.

"Our divers, our firemen put in the greatest possible effort to recover the bodies, but unfortunately this work wasn't fully completed," he said.

"I feel admiration for the residents of Giglio, the local authorities, the citizens and the extraordinary security forces for all they have done," the president added.

Napolitano urged that investigations shed full light on the causes of the disaster.

The Costa Concordia ran aground with 4,229 people on board near the Tuscan island of Giglio on January 13.

Thirty-two people are now believed to have died in the tragedy, even though the families of 15 still officially missing are clinging to the desperate hope that their loved ones may still be alive.

Captain Francesco Schettino, who faces charges of manslaughter and abandoning ship before all passengers were evacuated, is under house arrest and considered the main person responsible for the wreck.

Schettino has admitted responsibility for the impact but has blamed the ship's faulty equipment.

There will be another service on Monday -- exactly one month on from the disaster -- on Giglio itself, led by local bishop Guglielmo Borghetti, to honour victims, survivors and rescuers.