The Southeast Asian regime pardoned hundreds of dissidents, journalists and a former premier under a major prisoner amnesty, intensifying a surprising series of reforms by the army-backed government.
At least 200 men and women have been freed, Reuters reported.
Prominent dissidents Min Ko Naing, Ko Ko Gyi, Mya Aye, Htay Kywe and Nilar Thein are among the released on Friday, family members told news-magazine The Irrawaddi.
Min Ko Naing was a leader of the 1988 student uprising against the regime and a leading democracy activist and dissident. He has spent the majority of the last 23 years imprisoned for his opposition activities.
Ko Ko Gyi is another former student activist. He was sentenced to 65 years for campaigning against the Junta. Nilar Thein , Mya Aye iand Htay Kywe were sentenced for 65 years too.
The government had already pardoned 6,000 people last October 12, just a few weeks before US Secretary of State Hillary Clinton made an historic visit to Myanmar.
Last week, democracy champion Aung San Suu Kyi was given the green light to participate to the April by-elections.
The new, nominally civilian government is undertaking a number of democratic reforms after years of brutal military repression in order to acquire international legitimacy and end the isolation of the country.
"Years of international calls to release long-detained political prisoners seem to have pushed the government to finally do the right thing," said New York-based Human Rights Watch's deputy Asia director Elaine Pearson.
"The next step for Burma's government is to allow international monitors to verify the whereabouts and conditions of remaining political prisoners."