Sweden's Accident Investigation Authority (SHK) says that no decision will happen this year on whether a further investigation is needed into the 1994 sinking of the MS Estonia ferry.
The SHK's lead investigator, Jörgen Zachau, told Swedish Radio that: "It won't be this year, it'll be after the turn of the year at the earliest."
A recent documentary has revealed a hole in the wreck's starboard hull, prompting speculation that the official explanation of the disaster, which claimed 852 lives, needs revising.
Part of the delay lies in getting cooperation of three countries – Estonia, Finland and Sweden, into circumventing an agreement which prevents disturbing the vessel's resting place – about 50 km south of Finland's Turku archipelago – in order to send down human or robotic divers.
The documentary, made by a Swedish filmmaker based in Norway, involved an illegal dive down to the wreck, so a second consideration is forming a position on whether to use illegally-obtained footage in any potential official investigation.
Raw unseen footage reportedly contains evidence of further damage to the hull, not shown in the documentary, which aired on the Discovery Channel in Sweden in September.
Zachau said that it would likely be up to authorities other than his own to form a position on the use of the footage.
The filmmakers, Henrik Evertsson and Linus Andersson, are charged in their home country with disturbing the peace Estonia's grave, which could carry a hefty fine or lengthy jail sentence.
The raw footage is nevertheless available for viewing in Norway, Zachau said, but noted no decision had been made whether to travel there either, both due to coronavirus quarantine requirements and questions over the potential value of the unseen footage.
The full interview Radio Sweden clip is here.
The official cause of the September 28 1994 sinking is a sheared-off bow visor, which became detached in rough seas while the ferry was traveling at speed, allowing water to penetrate vehicle decks and rapidly compromise the vessel's stability.
One-hundred-and-thirty-seven people survived the sinking, the largest in European waters during peacetime and the second-largest peacetime maritime disaster involving a European vessel, after the Titanic.
The Estonian government proposed a fresh investigation earlier this month, and awaits decisions from Sweden and Finland.
The original investigation was concluded in 1997.
Editor: Andrew Whyte