MYANMAR'S military government has freed hundreds of political prisoners from the notorious Insein prison, including Aung San Suu Kyi's party spokesman and a famous comedian Zarganar, local media reported.

Minutes after military ruler Min Aung Hlaing's speech on Monday, state television announced more than 5,600 people arrested or wanted over their roles in anti-coup protests would be freed in an amnesty on humanitarian grounds.

The release was described by some activists as a ploy by the ruling military to try to rebuild its international reputation after the Association of Southeast Asian Nations (ASEAN) took the rare step of excluding the junta chief from its summit.

U.N. Special Rapporteur Tom Andrews on Twitter welcomed the release but said it was "outrageous" that they were detained in the first place.

"The junta is releasing political prisoners in Myanmar not because of a change of heart, but because of pressure," he said.

The junta has released prisoners several times since the February coup.

ASEAN decided to invite a non-political representative to its Oct. 26-28 summit, in an unprecedented snub to the military leaders behind the coup against Aung San Suu Kyi's elected government.

"They came to me today and said they will take me home, that's all," Monywa Aung Shin, a spokesman for Aung San Suu Kyi's National League for Democracy (NLD) party, told local media Democratic Voice of Burma late on Monday on his way home from prison.

Monywa Aung Shin was arrested on February 1 and had spent eight months in prison.

Photos and videos posted on social media showed detainees reunited with weeping family members.

Other images showed a succession of buses leaving the rear entrance of the jail, with passengers leaning from windows and waving at crowds gathered outside.

Myanmar's prison department spokesman and junta spokesman were not immediately available for comment.

More political prisoners including parliamentarians and journalists were freed on Monday in other towns including Mandalay, Lashio, Meiktila and Myeik.

However, 11 out of 38 people released from Meiktila prison in central Myanmar were arrested again according to local media Democratic Voice of Burma.

Reuters could not independently verify this information.

Myanmar has been in turmoil since the coup, which ended a decade of tentative democracy and economic reform.

Security forces have killed more than 1,100 people according to activists and the United Nations and arrested over 9,000 people including Suu Kyi, according to rights group Assistance Association for Political Prisoners, which documents killings and arrests.