The judge in the Pirate Bay case, Tomas Norström, has been a member of several of the same copyright protection organisations as several of the main entertainment industry representatives, Sveriges Radio's P3 news programme reports.
Peter Althin, the lawyer who represents Pirate Bay spokesperson Peter Sunde, has announced that he plans to demand a retrial.
"I will point that out in my appeal, then the Court of Appeal (Hovrätten) will decide if the district court decision should be set aside and the case revisited," Althin said on Thursday.
Althin is very critical of the judge's actions in the case and argues that the defence should have had an opportunity to review the circumstances.
"In the autumn I received information that a lay judge could have similar connections. I sent these to the court and the judge was excluded in order to prevent a conflict of interest. It would have been reasonable to then review this situation as well," Althin said.
Ola Samuelsson, the lawyer representing Gottfried Svartholm Warg, concurred with Althin in his assessment of the situation.
"All types of interest conflicts are a problem for the judiciary. It should be a matter of course as a judge to ensure that you keep your house in order. This is a high profile case and that is an additional reason to keep a check," Samuelsson said.
Samuelsson said on Thursday that he has not yet decided whether to join Per Althin and demand a retrial.
High profile attorney Leif Silbersky is one of a number of experts who concurred with Althin and Samuelsson in believing that judge Norström's various memberships represent a conflict of interest.
"A retrial is a possibility, but in that case the lawyers will have to take this up immediately," Silbersky told Sveriges Radio.
Pirate Party chairman Rickard Falkvinge has called for the verdict to be scrapped.
"The copyright lobby has really managed to bring corruption to Sweden," he said in a statement.
One of the groups of which Norström is a signed up member is Svenska föreningen för upphovsrätt ('the Swedish Copyright Association'), where he is joined by Henrik Pontén, Peter Danowsky and Monique Wadsted, all of whom represented the entertainment industry in the case against file sharing site The Pirate Bay.
The judge also sits on the board of Svenska föreningen för industriellt rättsskydd (Swedish Association for the Protection of Industrial Property), a group actively advocating for more stringent copyright laws.
Norström argues that he was not however swayed in his judgement by involvement with copyright protection groups.
"My view has been that these activities do not constitute a conflict of interest," Norström told Sveriges Radio.