SINGAPORE - The news that no new deputy prime ministers will be appointed at the next Cabinet reshuffle has taken some political observers by surprise, but they said this will allow the fourth generation of leaders to prove their mettle to Singaporeans.

Prime Minister Lee Hsien Loong's remarks on Friday (Jan 26) suggest there will still be a question mark over who his likely successor is even after the reshuffle.

"It's surprising but I do understand why PM has said this," said former People's Action Party (PAP) MP Inderjit Singh.

"The 4G leaders have not had enough experience. It's important that they can independently lead policies and succeed. There hasn't been enough of that kind of opportunity for them."

Institute of Policy Studies deputy director Gillian Koh noted that each of the three men who are widely considered front runners for prime minister needs time to address certain gaps in their resume.

The trio are Finance Minister Heng Swee Keat, Minister in the Prime Minister's Office Chan Chun Sing and Minister for Education (Higher Education and Skills) Ong Ye Kung.

"Mr Chan is still deeply ensconced in NTUC, so it will take time to find his replacement and for him to go back to a policymaking capacity," she said.

"Mr Ong does not lead a GRC, and it's hard to envisage a PM-in-waiting who doesn't head a GRC, but this will take time," she added.

Mr Heng has stepped back into his role full time for a year now since he suffered a stroke, she noted, but had kept public engagements to a minimum until late last year.

"So he needs time to get back in the saddle, meet different constituencies and rekindle those links to make up for the time when he was recovering."

Political observer Derek da Cunha said the next prime minister "has to be seen by everyone as having the stature that approximates his three predecessors".

In a Facebook post on Friday night, he wrote: "Whoever the person might be from within the 4G team, ideally, he has to get more exposure - domestically and internationally - and, more experience in terms of Cabinet portfolios.

"This is because the PAP has established standards whereby a person for high political office has to be very knowledgeable - widely read - charismatic, have presence, be a polished speaker, be quick thinking, and where ordinary folk are able to relate to him or her."

Waiting a bit longer to name a new deputy prime minister will keep the focus on the work being done by the fourth-generation leadership, rather than on one personality, said political analyst Mustafa Izzuddin.

"It's clear from PM's comments that he wants there to be more focus on the progress being made by the team as a whole, and what the team is doing to take Singapore forward."

Even so, he expects more clarity on who will be the next prime minister by the end of 2018.

"It's worth asking who will take the PAP to the next General Election, which has to take place by 2021. If you want to give the new leader a strong mandate then you need to give him time to prepare the team and lead it to victory at the GE."