Polish officials said he had come to Poland for paramilitary training.
Interior Minister Stanislaw Zaryn said that the country's security agency had found that the man posed a threat to security, reports international news agency AP.
The 22-year-old man, named in Swedish media as Anton Thulin, was sentenced to one year and 10 months in jail in Sweden in connection with a planned bomb attack in Gothenburg almost three years ago. The explosives were found, undetonated, on a camping site near a home for asylum seekers.
The incident was investigated as part of a series of three bomb incidents in Gothenburg in 2016. One of them left an immigration office staff member seriously injured with wounds to his legs.
Two other men were also charged in connection with the incidents, with one jailed over all three and the other jailed in connection with two of them.
Thulin told the court at the time that he was no longer a member of the neo-Nazi Nordic Resistance Movement.
The Swedish security police Säpo, when approached by Swedish news agency TT, declined to say whether or not they had cooperated with their Polish counterparts to seize the man.