A grassroots adviser will be appointed to Marsiling soon to take care of its residents, said Prime Minister Lee Hsien Loong.
He made the announcement yesterday in a letter to Madam Halimah Yacob, who resigned as MP and Speaker of Parliament to stand in the presidential election.
Observers said the incoming adviser is likely to be Malay, noting the three remaining MPs for Marsiling-Yew Tee GRC are Chinese.
To stand for election in a GRC, teams must field at least one candidate from a minority community.
ISEAS - Yusof Ishak Institute research fellow Norshahril Saat said: "It is for the party to decide. But symbolically, it is likely to be a Malay adviser.''
One possible candidate is Mr Shamsul Kamar, 45, the People's Action Party's branch chairman in the Kaki Bukit ward of Aljunied GRC, which the Workers' Party holds.
But Mr Shamsul told The Straits Times: "I am not aware of any news of me going to Marsiling."
He added: "My focus is on my constituency. Since the last election, we have a lot of things on our minds, including elderly issues, jobs and infrastructure development."
Another possibility is Mr Hawazi Daipi, who stepped down as MP for the Marsiling ward in 2015.
Mr Hawazi, a retired senior parliamentary secretary, was appointed Singapore's non-resident representative to the Palestinian Territories last November.
There is no legal requirement to call a by-election to fill the spot Madam Halimah vacated.
When Mr Lee Kuan Yew died in March 2015 and Senior Minister of State Balaji Sadasivan died in September 2010, no by-election was held in their GRCs.
When Dr Ong Chit Chung died in 2008, Madam Halimah and her fellow MPs looked after his Bukit Batok ward in Jurong GRC until the 2011 General Election. No by-election was held.
None of the three deaths left the GRC without a minority MP.
The Singapore Democratic Party (SDP) said it will "actively explore legal remedies" to compel the Government to call a by-election in the GRC. The Reform Party agrees with it.
The SDP had contested in Marsiling-Yew Tee GRC in the 2015 General Election.Its argument essentially is that Madam Halimah's resignation lessened the degree of representation of Marsiling-Yew Tee's Malay community in Parliament.
This argument was addressed in Parliament by Minister in the Prime Minister's Office Chan Chun Sing in February.
He said the purpose of the GRC scheme was to ensure enough minority MPs, and to discourage candidates from campaigning on issues of race or religion.
These key goals would not be affected if one member of the GRC left. Hence, no by-election needs to be called if a minority candidate leaves the GRC, said Mr Chan.