Three potential candidates from the public sector have been accompanying People's Action Party (PAP) MPs at community events in recent days.
One of them, Ms Rahayu Mahzam, 35, yesterday confirmed with The Straits Times that she had resigned from her post as deputy registrar of the Syariah Court.
The two others are Second Permanent Secretary for Trade and Industry Chee Hong Tat, 42, and senior police officer Melvin Yong, 43.
Public servants are traditionally introduced last as new candidates by the PAP as they must resign before they can enter politics.
Most of the party's other potential candidates for the next general election have been on the ground in the constituencies they are likely to stand in, PAP organising secretary Ng Eng Hen said on Sunday.
Last weekend, after electoral boundary changes were made public last Friday, the trio were seen with MPs at grassroots events.
Ms Rahayu was in Bukit Batok East with Jurong GRC MP Halimah Yacob on Sunday. Asked if she would stand as a candidate, she said: "I would be happy to serve if chosen, but I will leave that decision for Prime Minister Lee Hsien Loong to make."
She has volunteered in Tampines West for about a year and recently did so in Bukit Batok East.
"I have been passionate about working with youth and helping disadvantaged families," she added.
Ms Rahayu, who also volunteered in Malay-Muslim organisations and is on the National Library Board and National Youth Fund advisory committee, said: "My involvement in the grassroots is a natural extension of my volunteer work that began many years ago."
She also said she would rejoin the law firm she worked in before she joined the public service.
Her presence fuelled talk among party activists that Madam Halimah, who is in charge of the Bukit Batok East ward, will move to another constituency. This may be Marsiling-Yew Tee GRC or Bukit Batok SMC. When asked about it, Madam Halimah said: "Where we will stand is up to the party to decide. I have been with Bukit Batok East for almost 15 years and am very fond of the place which has become my second home."
The other two senior civil servants were seen in the wards of MPs expected to retire from politics.
Mr Chee was with Bishan-Toa Payoh GRC MP Hri Kumar Nair and residents at a party on Saturday. Mr Chee was chief executive of the Energy Market Authority and principal private secretary to former prime minister Lee Kuan Yew.
Mr Nair, a two-term MP and senior counsel in a law firm, serves the Thomson-Toa Payoh ward. Activists said he has asked to leave politics. That will make him the third in the GRC to leave, along with former deputy prime minister Wong Kan Seng and former Central Singapore District mayor Zainudin Nordin.
On Sunday, Assistant Commissioner of Police Melvin Yong was at Punggol North, the ward of Pasir Ris-Punggol GRC MP Penny Low, a three-term MP. They attended a street parade to celebrate racial and religious harmony.
Mr Yong, director of the police public affairs department since last June, was previously commander of Clementi Police Division.
Mr Nair declined to comment, while Mr Chee, Mr Yong and Ms Low could not be reached.
•Additional reporting by Rachel Au-Yong