"Sports have long had difficulty [taking action] because they have been regarded as non political," said Winfriede Schreiber, head of the Brandenburg state intelligence service.
But she said sports clubs were increasingly recognizing the danger. "More and more, the associations realize that that they must profess their dedication to democracy," she said.
The kick-boxing scene in the Lausitz region has a bad reputation for having many neo-Nazi members, despite many successful anti-fascist initiatives in the area.
"Neo-Nazis do not exist in a vacuum. They have families, go to school, develop careers, play sport or are in the volunteer fire brigades," said Schreiber.
"Many neo-Nazis are in no way uneducated these days, and can be successful in their careers. Civil society now has the problem of how to deal with them. In small places this is sometimes particularly difficult. The boys are the sons of people, or brothers. And often enough it is pure chance where someone ends up - in the fire brigade or the Nazis."
She said neo-Nazis were using sports groups to reach young people and either influence their thinking, or recruit them to their gangs. They attended club meetings and sports events wearing neo-Nazi T-shirts or showing off their tattoos - and then organise tournaments at which their scene meets, she suggested.
"The neo-Nazis pull in young people in this way and alienate them from democracy. They use normal life to push their movement," she said.
"It doesn't always work. But those concerned are often successful and are therefore admired. Apart from that many neo-Nazis are successful professionally these days - they run pubs or produce T-shirts which are popular with young people and a profitable field. Some of them are sponsors of sports clubs or events. Over and above this, they have close connections to security companies. This interleaving is dangerous because it intimidates."
She said that the case of Nadja Drygalla, the rower who represented Germany at last year's Olympics but who was sent home early after her relationship with a neo-Nazi became public, showed how difficult it could be to keep even high level sport clear of far-right influences.
"I have great respect for small clubs or societies which have to find a way to deal with each other every day," said Schreiber. She said a mobile advice centre was available to offer help around Brandenburg, while advisers were working with kick boxing clubs in Cottbus to help them deal with the topic.
"One cannot of course forget the economic aspect. We have been worried for years by a group of fans of the Energie Cottbus Football Club because of their far-right connections. But the club has not yet been able to clearly make a move against them. Things such as annual tickets or sponsorship money must play a role."
She said that an angling club had provided a great example when members told far-right colleagues they had to decide what they wanted to stay in - their fascist groups or the angling club. "Volunteer fire brigades have also made great progress in this regard - and there we can see the success of advisers and discussions," said Schreiber.