State radio and television announced on Friday that the prisoners had been released in recognition of their good conduct, for the "social consideration of their families" and so they can participate in the general election planned for 2010.
In recent months, the military government's courts have sentenced more than 100 dissidents - including some of the country's most prominent political activists - to lengthy jail terms extending well beyond next year's poll.
However, the government denies it has incarcerated any politicial prisoners, insisting all those jailed have committed crimes.
'Roadmap to democracy'
The amnesty has been billed as part of a seven-step "roadmap" to restore democracy to Myanmar and followed a five-day visit by Tomas Ojea Quintana, the UN's human rights rapporteur.
But Western governments have dismissed such moves by the government as a charade while human-rights groups have accused it of seeking to eliminate all political opposition before holding the election.
Rights campaigners estimate around 2,100 political prisoners have been detained by the government, including Suu Kyi, a Nobel Peace Prize laureate, who is under house arrest.
Suu Kyi has spent 13 of the past 19 years in detention without trial and when the government released 9,002 prisoners last September, only around a dozen political detainees were released.
Myanmar's ruling generals came to power in 1988 after crushing a pro-democracy uprising.
The government called elections in 1990 but refused to abide by the results when Suu Kyi's party won a decisive victory.