There was no sign former leader Aung San Suu Kyi, who was ousted in the military takeover in 2021 and has been held virtually incommunicado since then, would be freed.
The amnesty comes two weeks before parliament is set to convene for its first session in more than five years following the recent election that critics said was neither free nor fair.
State-run MRTV television reported on Monday that Senior General Min Aung Hlaing, the head of the military government, pardoned 10,162 prisoners, including 7337 convicted under a counterterrorism law, on Peasants' Day, a national holiday honouring farmers.
A separate statement said 12,487 people who were either being prosecuted under that law or were in hiding, would receive amnesty and have their incitement cases closed.
The law carries a potential death penalty and was widely used to arrest and imprison political opponents, journalists, and others involved in dissent since the 2021 army takeover.
Ten foreigners would also be released and deported from Myanmar, it said in a separate statement.
Mass amnesties to mark holidays are not unusual in Myanmar. The prisoner releases began on Monday but may take a few days. The identities of those released were not immediately available.
According to the Assistance Association for Political Prisoners, an independent organisation that keeps detailed tallies of arrests and casualties linked to the nation's political conflicts, more than 22,800 political detainees were in detention as of last Friday.
They include the 80-year-old Suu Kyi, who is serving a 27-year sentence after being convicted in what supporters have called politically tinged prosecutions.
18°C