Two men are also being held on suspicion of unlawful detention and one for unlawful threats, according to the police.
The six team leaders are reported to have been assaulted in connection with being locked up and two people are reported to have been tied up.
The detained men are from Vietnam and are aged between 19 and 27-years-old.
There have been a series of protests involving immigrant workers who came to Sweden to pick berries in northern areas.
The Local reported on Tuesday that around 120 workers from Vietnam staged two demonstrations. Aside from the incident at the school building in Särna in Dalarna, around 50 Vietnamese workers staged a sit down protest along a road in the town of Nordmaling.
Furthermore on Friday around 100 Chinese berry pickers went on a 15-kilometre overnight march from Långsjöby outside of Storuman on Thursday to protest their salaries and conditions.
Thousands of seasonal workers from Asia, most of them from Thailand, come to Sweden each summer mainly to pick wild berries in the north under sometimes
difficult working conditions.
After a disastrous season last year sent many of the foreign berry pickers home weighed down by debt instead of profits, they have this year for the first time been provided with contracts guaranteeing them a monthly wage of at least 16,372 kronor ($2,321).
Some Swedish unions have however said that the minimum salary is insufficient, producing evidence that in some cases it is hardly enough to cover the money the workers have to shell out for things like plane tickets, housing and car rental.