The commission supported police in its findings that no technical evidence exists in support of sabotage claims, reports broadcaster NRK.
Neither did the investigation carried out by the commission reveal any information suggesting that the way in which the ferry was insured was a motive for arson, according to the report.
“The new police inquiry into the incident has the character of a well-organised and managed project,” wrote the commission, adding that the police investigation “was organised in a way that may have seemed to have limitations,” reports NRK.
But the commission concluded nonetheless that the police investigation was satisfactory.
The commission found that central elements of the case were reviewed and assessed by police, in addition to the collection of extensive witness statements and “a significant number” of documents.
“That there was, in such a comprehensive body of material, not found any basis for the given theories, supports the police and prosecutor's conclusions in this case,” wrote the commission.
But relatives of the victims described the conclusions of the commission as “sad, worrying and shocking,” news agency NTB reported Thursday.
“People waiting for answers will not get them from you. You are deceiving people into thinking that this is the truth. It is not,” Ole Arnt Westberg of the Support Group for the Scandinavian Star Accident said after the report was presented in parliament.
Sigurd Klomsæt, lawyer for many of the victims' families, also said that he was shocked by the report.
“Many elements have been kept hidden. That's sad,” Klomsæt said according to NTB.
The head of the commission told the news agency that the report reflected the truth.
“Our working method was to show what is likely to have happened based on verifiable facts,” Frank Kjetil Olsen said.
Several theories exist as to the course of events that led to the disaster, which claimed 159 lives, on board the ferry on 7th April 1990.
Last year, a retired inspector said he believed that the fire had been started deliberately by two members of the crew.
A new investigation was opened by police later in 2016, but was ended without charges, prompting complaints from victim support organisations.
Police said when they dropped the 2016 investigation that their conclusion from 1990 – that the first fire on the ferry was started intentionally – had not changed.
Norwegian police initially claimed that the fire was set by a Danish truck driver who died in the flames, but charges against him were dropped in 2014 when a police report stated that there was not sufficient evidence of his guilt.
The group "Foundation for Arson Investigation into Scandinavian Star" contested the 2016 investigation's conclusions, with one member of the group accusing the police of having removed vital photographs from the investigation materials.