The report by Expo, which is an organisation that researches racist groups, estimated that there were 159 active members of the Nordic Resistance in Sweden in 2015.
More than 30 per cent of those identified had no previous history of being part of the extreme right wing, Expo said.
“It means that they have recruited new individuals,” said Expo researcher Jonathan Leman to Swedish Radio.
Most of the new recruits identified, totalling 14 individuals, were based in Skåne and Blekinge.
The Nordic Resistance Movement, an right-wing extremist organisation, has a history of violence. It has around 250 active members in Sweden, Norway and Finland.
Expo’s latest figures are an estimate. It is difficult to get precise numbers as the Nordic Resistance Movement is a closed group. Its spokesman did not want to comment on the story to Swedish Radio.
Leman said he thought the group had attracted more members due to the fact it is changing direction, including starting a political party.
The group held widely publicised marches this year of around 300 supporters in Borlänge in May and an estimated 600 in Stockholm in November.
The head of police intelligence in Dalarna, Thomas Hellgren, said those activities could have been significant in the drive to recruit new members.
“It is not an unknown phenomenon that recruitment to these groups increases in connection with specific events,” he said.