Every cruise ship passenger will be given a mandatory safety briefing, including on-ship evacuation procedure, before leaving port under new rules announced by the industry in the wake of the Costa Concordia disaster.

The three major organisations representing cruise lines have agreed that the passenger safety briefing, or muster drill, must take place immediately rather than within 24 hours as currently required under maritime law.

When the Costa Concordia ran aground off the Italian coast on 13 January, hundreds of passengers who had boarded earlier that day in Rome were yet to be told what to do in an emergency.

At least 32 people are believed to have died in the disaster, with 17 bodies recovered and 15 recorded passengers still unaccounted for, after an evacuation that took several hours and was marked by confusion and the lack of accessible lifeboats.

Many operators already carry out muster drills, where passengers are taught how to put on life jackets and go to emergency exits, before the cruise ship leaves port. Cruise lines will now be required to give immediate instruction to any passengers joining the ship after the drill has taken place.

The Cruise Lines International Association said that the requirement had been voluntarily initiated as part on an ongoing safety review it is conducting, and it may be recommending further action.

The seafarers' union Nautilus has warned of possible problems in the mass evacuation of ever-larger ships, with some now carrying over 5,400 passengers.

Francesco Schettino, the captain of the Concordia, remains under house arrest pending investigation.