The complaint by survivors and families of victims, first filed in 1996, is directed against certification agency Bureau Veritas as well as shipbuilder Meyer Werft. The official investigation into the sinking of the ferry hinted at construction flaws, ERR's Aktuaalne kaamera newscast reported on Friday evening.

Hearings in the matter are held in Nanterre just outside Paris, the seat of Bureau Veritas, and started on Friday. The reason for the delay of more than two decades lies in the agency as well as the shipbuilder's efforts to fend off the complaint. Also on Friday, a good part of the hearings was about whether or not the complainants have a right to move against Bureau Veritas and Meyer Werft at all, and where the matter needs to be dealt with, whether in a French, a German or a Swedish court.

Over the following hours, details of the ship's construction were discussed. The investigation following the sinking of the Estonia found that the disaster was caused by design flaws, such as locks on the ship's bow doors having been too weak, and the loading ramp being connected to the bow visor. The latter eventually came off, and tore off the loading ramp as well, upon which the loading deck of the ferry was flooded, which in turn caused it to capsize.

Schmill & Lombrez, the law firm representing the survivors and victims' families, see the classification agency as the main culprit in the case.

"If there was an issue with the original design of the ship, then Bureau Veritas should have directed attention to it, and deal with it either right away or later on," attorney Erik Schmill said. "If the issue is one of the ship's maintenance, the same applies."

Bureau Veritas gets paid to check ships, but now claims it had nothing to do with any of what preceded the Estonia shipwreck, Mr Schmill said. But if that is the case, "What are they getting paid for then?" he asked.

Neither the agency nor shipbuilder Meyer Werft were ready to comment on the complaint. In court, they argued that the ship was in a bad state technically, that its maintenance had been lacking, and that the same applied to its crew, which for instance had operated the ferry at too high speeds in the night of its sinking.

While they insist that their actions concerning the factors in their control complied with requirements, Mr Schmill thinks otherwise. "Their checks were very formal and in practice were lacking, taking into account what we've heard this afternoon," he said after the Friday hearing.

Meanwhile Bureau Veritas has questioned the independence and trustworthiness of the investigators of the disaster.

MS Estonia sank in the early hours of 28 September 1994. The ship was en route from Tallinn to Stockholm, scheduled to arrive at 9.30 local time. The ferry carried 989 people that night, 852 of which died when the Estonia sank after her bow visor came loose and was eventually torn off in rough weather.