MARSEILLE (AFP) - Human error was probably to blame for the death of a Filipino crewman on the world's biggest cruise liner the Harmony of the Seas, a prosecutor said on Wednesday (Sept 14).

The 42-year-old electrical engineer was killed on Tuesday when a lifeboat became detached from the liner during a safety drill, sending it plunging 10m into the water while the ship was docked in the French port of Marseille.

Marseille prosecutor Xavier Tarabeux said the investigation had so far found no sign of "faulty equipment".

Investigators are now examining whether mistakes were made in the use of the lifeboat.

"The investigation is shifting towards the theory that human error was to blame," Mr Tarabeux said.

Three Filipinos and an Indian man were also injured in the incident.

The men were carrying out a routine weekly safety drill on the 120,000-tonne ship.

Witnesses are being questioned and the Harmony of the Seas, which had been due to sail for Italy on Tuesday, has been forced to remain in port in Marseille while the investigation continues.

The ship's owners, Florida-based Royal Caribbean, said two of the injured men had been discharged from hospital, while two others who were more seriously injured were still receiving treatment.

Harmony of the Seas entered service less than four months ago, in late May.

At 66m, it is the widest cruise ship ever built, while its 362m length makes it 50m longer than the height of the Eiffel Tower.