The Union Election Commission (UEC) said Thursday that it would hold polls in November or December to fill 13 vacant seats in the Upper House, six in the Lower House and 11 in regional and state assemblies.
The precise date would be announced three months ahead of the polls, UEC chairperson Tin Aye said.
"We are now preparing to contest in all 30 constituencies," said Nyan Win, spokesman for the National League for Democracy (NLD) party of opposition leader Aung San Suu Kyi.
It will be second round of by-elections since the quasi-civilian government led by President Thein Sein took power in March 2011.
DPA