A precedent may have been set last week with the release of an asylum seeker from a expulsion center that is part of the detention system.
On Thursday, Tallinn Administrative Court freed a Vietnamese citizen who has been held at the Harku expulsion center since last September. The person is instead now housed in the reception center.
The Estonian Human Rights Center had petitioned to free the individual, who had requested protection from Estonia.
"Detaining an individual applying for refugee status is unconstitutional if there is no legal basis for detention, such as endangering national security," the Human Rights Center said in a statement.
The head of the organization's refugee department, Kristi Toodo, said the ruling marks an important precedent.
"It may change future court practice, with regard to lodging refugee applicants at reception centers instead of detention centers," Toodo said.
Until now, the Police and Border Guard Board has successfully applied for the extending the detainment of the individual every two months.
Vietnamese migrants have made news in Estonia on several occasions. In 2012, 56 Vietnamese citizens were caught illegally migrating to Estonia.