SINGAPORE - Mr Pritam Singh is emerging as the top choice for Workers' Party's next leader, with three of its other MPs publicly ruling themselves out of the race and endorsing him.

They are Non-constituency MPs Daniel Goh, Leon Perera and Dennis Tan. Ms Sylvia Lim has also made it clear she is not interested in the position, saying she intends to run for her current role as party chairman.

Party insiders said Mr Singh, the party's assistant secretary-general, is also the clear choice of current party secretary-general Low Thia Khiang.

However, a question mark hangs over whether fellow Aljunied GRC MP Chen Show Mao will challenge Mr Singh for the role.

When approached by The Straits Times Monday night on whether he would stand for election as party secretary-general, Mr Chen, 57, declined comment.

During the last round of the biennial central executive committee elections, in 2016, Mr Chen mounted an unprecedented challenge against Mr Low. Mr Chen lost then, with 45 votes to Mr Low's 61.

Mr Low, 61, announced last November that he would be stepping down to make way for new blood.

While Mr Singh, 41, a lawyer, is generally seen as the front runner, the names of other WP MPs such as Dr Goh and Mr Tan have also been thrown up as possible candidates.

On Monday, they were unequivocal in stating that they would not run for the position, saying that Mr Singh is the best person for the job.

Dr Goh, 44, a sociologist, described Mr Singh as a "humble servant-leader who knows his own flaws, works closely with the party grassroots and exhorts them to unite for the common good of Singapore and Singaporeans" in a Facebook post.

Mr Tan, 47, told The Straits Times: "I fully agree with Daniel that Pritam is more worthy to be the next secretary-general.

"My view is that the secretary-general must be able to lead us in Parliament since we are the only opposition party. To me, experience in Parliament and being able to speak on issues is very important."

Also throwing his support behind Mr Singh, Mr Perera, 46, said: "He is a tried and tested leader who has served creditably in many roles in the party and town council, is effective at the grassroots and has performed well in Parliament."

Ms Lim, meanwhile, said that she believes that she can still contribute as party chairman.

Hougang MP Png Eng Huat and Aljunied GRC MP Muhamad Faisal could not be contacted.

When approached, Mr Singh simply said: "Ultimately, the cadres have to decide who they want to lead them as the next secretary-general."

On Dr Goh's comments on him, Mr Singh would only say: "He is at liberty to say whatever he wants. Whatever he said does not apply only to me, it applies to quite a few of us in the party."

He declined to say more.

The elections will be held on April 8, the WP revealed over the weekend. This means that the party will have a new leader when Parliament reopens in May after a mid-term break.

The signs have been pointing to Mr Singh possibly taking the helm since he was appointed the party's assistant secretary-general in 2016, a post that had been vacant since 2006.

In recent months, he has also increasingly been the party's public face. He chaired the committee on the party's 60th anniversary celebration last year and represents it in media interviews and in the recently set up parliamentary Select Committee on fake news.

He is also chairman of its Aljunied-Hougang Town Council.

Party insiders said Mr Singh has a high chance of success, given his popularity in the party and among Aljunied GRC residents.

He had garnered the highest number of votes among a list of 21 people vying for positions in the party's top decision-making body in 2016. Mr Low and Ms Lim were not on that list.

His Eunos ward also had the highest vote share among the five wards in Aljunied GRC, which the WP retained by a narrow margin in the 2015 general election.