Meghalaya PHE Minister Renikton Tongkhar and four other sitting MLAs of the state resigned from the Assembly on Wednesday.
Besides Tongkhar, those who resigned are Trinamool Congress MLA Shitlang Pale, suspended Congress MLAs Mayralborn Syiem and PT Sawkmie and Independent MLA Lambor Malngiang, he said.
The five are set to join the United Democratic Party (UDP), sources in the party claimed.
The Assembly currently has 42 members.
"We have received the resignation letters of five MLAs. Assembly Speaker Metbah Lyngdoh has received them in person," Assembly commissioner and secretary Andrew Simons told PTI.
Lyngdoh is the president of the UDP, which is a key alliance of the Conrad Sangma government in the state.
Sangma, who is the National People's Party supremo, leads the ruling six-party Meghalaya Democratic Alliance. The BJP, which has two MLAs, is part of the MDA. The MDA government is the third coalition to last its full term in power in the state in over 50 years.