[1] The seat became vacant after the death of the incumbent assemblyman, Eddie Ng Tien Chee on 20 July 2018 in a traffic accident on the Cheras–Kajang Expressway.

This was the second casual vacancy in the Assembly since the May 2018 general election after Sungai Kandis, which held a by-election in August 2018.

[3] In the last 2018 general election, Ng defeated Barisan Nasional (BN)'s Malaysian Chinese Association (MCA) candidate, Lim Chin Wah and Mohamad Ibrahim Ghazali of Pan-Malaysian Islamic Party (PAS), with a vote majority of 35,538.

While PAS had decided not to contest to make way for the BN candidate, just liked in the case of the Sungai Kandis by-election a month earlier.

[6] Pakatan Harapan (Democratic Action Party) Wong Siew Ki was serving as the Seri Kembangan assemblyman and Selangor state executive councillor Ean Yong Hian Wah’s political secretary and she was also Subang Jaya municipal councillor since 2016 then.