Parti Rakyat Malaysia (PRM), one of Malaysia's oldest political parties, will be fielding a candidate for the upcoming Balakong by-election.
It is the second party to commit to the by-election after DAP, which won the seat by a landslide during the May 9 general election.
PRM secretary-general Koh Swe Yong said the party wants to join the by-election because there are very few opposition lawmakers in the Selangor Legislative Assembly.
"The Selangor government has too much power. This is not healthy for a democratic system... there is no check and balance.
"They rakyat must build a strong check-and-balance system if they wish to see democracy.
"In this new scenario, PRM stands a chance (in the by-election)," Koh said.
PRM was established in 1955 by Ahmad Boestaman as a leftwing party , but has had very limited impact on elections.
The party has not had any representatives in Parliament since 1959, although some of its former members were elected to public office after joining other parties.
After sitting out of the 2013 elections, PRM re-emerged for the May 9 elections, contesting six parliamentary and 35 state seats in Selangor, Penang, and Kedah.
The Balakong by-election follows the death of incumbent Eddie Ng on July 20. DAP will be representing Pakatan Harapan for this election.
Balakong was an MCA stronghold until the 2008 general election. So far, MCA has yet to state whether they will field a candidate.