Prison officials say the amnesty to include former student activists and a prominent monk.
Myanmar’s government is due to free around 651 prisoners, including political detainees, on Friday in a move to further reform the country.
Among those to be released are prominent Buddhist monk Shin Gambira and a group of former student activists who were jailed as a result of an uprising in 1988, according to prison officials speaking to the Reuters news agency.
An official from Taunggyi Prison in Shan State said two prominent dissidents, Ko Jimmy and Ko Zaw Thet Htwe, would be released.
“We are going to take them to the bus terminal later this morning,” the official said.
Phyo Min Thein, brother-in-law of Htay Kywe, one of the leaders of an acitivist group known as the “88 Generation Students Group”, said: “I’ve got confirmation that Ko Htay Kywe and almost all members of the 88 Group and other prominent figures like Shin Gambira and U Khun Tun Oo will be released today.”
Activists said they expected more political prisoners to be among those freed in Friday’s amnesty, a step that could help pave the way for the lifting of economic sanctions by the European Union and soon thereafter by the United States.
Myanmar has initiated a multitude of reforms since a civilian government was allowed to take power in March after almost half a century of rule by the military.
Some political prisoners have been freed, media restrictions eased and the government has initiated a dialogue with Nobel laureate Aung San Suu Kyi.
US Secretary of State Hillary Clinton visited Myanmar in early December and promised to support more aid and consider installing an ambassador.
The next major step in the reform process will be by-elections already announced by the government and set for April, in which Suu Kyi and her National League for Democracy (NLD) will take part.
The US and Europe have said freeing political prisoners is crucial to even considering lifting sanctions that have isolated the former British colony also known as Burma and, over the years, pushed it closer to China.
Myanmar freed about 230 political detainees in a general amnesty on October 12.
A senior political adviser to President Thein Sein told Reuters in November that hundreds of political detainees may soon be released.
The exact number of political prisoner behind bars is unclear, although estimates by rights groups and unofficial statements by the home affairs minister range from about 400 to about 2,000.