SINGAPORE - At least one of the top three contenders to become Singapore's fourth prime minister already has someone in mind for the job - and it does not appear to be himself.

Education Minister (Higher Education and Skills) Ong Ye Kung said in an interview with The Straits Times earlier this week: "I am shaping up in my mind someone who can be the leader amongst us. I am sure my colleagues are thinking of the same issue too."

He declined to name the person he had in mind. On whether the ministers can pick themselves, he said "that doesn't sound like it is in the right spirit", adding that he did not know what the convention was as it is his first time taking part in the process.

Mr Ong, 48, is among a trio of ministers who are tipped to be in contention for the job. The other two are Finance Minister Heng Swee Keat, 56, and Minister in the Prime Minister's Office Chan Chun Sing, 48.

Political observers approached said Mr Ong is still in the race despite saying he has someone in mind.

They said while he may well nominate someone else, others in his cohort can still pick him, adding it is still too early to rule out any of the three front-runners.

When asked how he decided on the person he intends to support, Mr Ong said he had taken into account the person's conviction and ability to drive long-term, important policy, as well as public and party support for the person.

On Thursday (Jan 4), the fourth-generation ministers said in a statement that they will choose a leader "in good time".

"Political stability has been the hallmark of Singapore and smooth leadership succession has instilled confidence among Singaporeans and our friends around the world.

"The younger ministers are keenly aware that leadership succession is a pressing issue and that Prime Minister Lee Hsien Loong intends to step down after the next general election. We are conscious of our responsibility, are working closely together as a team, and will settle on a leader from among us in good time."

The statement was signed in alphabetical order by a group of 16 Cabinet ministers and office holders.

The 16, besides the trio are: Senior Minister of State for Communication and Information and Health Chee Hong Tat, 44; Minister for Culture, Community and Youth Grace Fu, 53; Senior Minister of State for Trade and Industry and National Development Koh Poh Koon, 45; Minister for Social and Family Desmond Lee, 41; Minister for Environment and Water Resources Masagos Zulkifli, 54; Minister for Education (Schools) Ng Chee Meng, 49; Senior Minister of State for Communications and Information and Education Janil Puthucheary, 45; Senior Minister of State for Finance and Law Indranee Rajah, 54; Minister for Trade and Industry (Industry) S. Iswaran, 55; Senior Minister of State for Culture, Community and Youth and Trade and Industry Sim Ann, 42; Speaker of Parliament Tan Chuan-Jin, 48; Minister in the Prime Minister's Office Josephine Teo, 49; and Minister for National Development Lawrence Wong, 45.

The comments came as interest in Singapore's much-discussed political leadership succession was piqued over the weekend by a Facebook post by Emeritus Senior Goh Chok Tong on New Year's Eve.

Mr Goh said he hopes the fourth-generation ministers will choose a leader among themselves in six to nine months' time - so that PM Lee can formally designate his potential successor before the year's end. It was the first time a senior figure from the People's Action Party (PAP) has publicly sketched out a timeline, and some party insiders believe that it was part of an attempt to pressure the younger leaders to come to a consensus.

Mr Lee has said that he intends to hand over the reins of Government to a successor by the time he is 70, in 2022.

This means that the next prime minister will have the shortest run-up phase. PM Lee was deputy prime minister for 14 years, while Mr Goh spent five years as first deputy prime minister.

Meanwhile, Minister in the Prime Minister's Office Josephine Teo told The Straits Times earlier this week there is "nothing unexpected" about Mr Goh's comment.

She said that the process of choosing a new PM is no different - with the fourth-generation ministers choosing one among them to lead.

"It's a tested process, it's worked well for us. It ensures that there is a strong team in place, so I think that is indeed what will happen," she said.

On the timing, she said Singaporeans have to wait until after Parliament opens in May with the President's address. Mr Lee has said he will prorogue Parliament this year.

"I fully appreciate that there are many Singaporeans who are also anxious to know how the process will continue to unfold but I think first things first, the President is making her inaugural address, I think we have to give due respect to the importance of this occasion."