When a group of Singaporean pupils and teachers climbing Mount Kinabalu in June 2015 were killed in an earthquake, the leadership that then Education Minister Heng Swee Keat displayed in responding to the crisis left a deep impression on researcher Mohamed Salihin Subhan.

Mr Heng was at the airport to comfort their parents, spoke personally to the students and teachers who survived the disaster, and went down and stayed in touch with their school to see how they were coping.

Mr Salihin, 26, said Mr Heng's actions and words "cemented him in my mind as a capable leader", adding: "Not only did he work round the clock to prepare the ministry's official response and actions after the disaster, he also gave very good speeches which helped the nation mourn."

Seven pupils and two teachers from Tanjong Katong Primary School were killed by falling boulders while ascending the 4,092m high mountain when the 6.0-magnitude quake struck on June 5, 2015.

While Mr Salihin likes Mr Heng for his leadership capability and comforting words in a time of crisis, retiree Lee Kuang Chye, 73, appreciates him for his character in dealing with complaints and concerns from constituents.

"One of my friends went to see him at a Meet-the-People Session and he was very patient," Mr Lee said in Mandarin. "It's rare to find people who really care about the ordinary people, but I think Heng Swee Keat is one of them."

The two were among 50 Singaporeans The Sunday Times spoke to after Mr Heng, 57, who is now Finance Minister, was named the People's Action Party's (PAP) first assistant secretary-general on Friday, making him the most likely candidate to be Singapore's next prime minister.

Mr Heng's fellow political office-holders in the PAP's fourth-generation leadership selected him to be their leader. And Mr Heng asked Trade and Industry Minister Chan Chun Sing, 49, to be his deputy. Mr Chan was named PAP's second assistant secretary-general on Friday.

Most people interviewed had confidence in Mr Heng's capability and experience - he was a senior police commander and helmed the Monetary Authority of Singapore (MAS) - and felt he was the most suitable leader for the next generation.

But a number also noted Mr Chan had strong credentials, was capable and had age on his side, making him a good deputy and possible PM.

Mr Chan was former army chief and led the Ministry of Social and Family Development, and the labour movement before taking up his current portfolio.

Temple volunteer Tan Kim Bee, 68, said that while both men are good, he feels that the Finance Minister "is able to connect better with the people, and seems easier to relate to".

"Mr Chan's approach is different. It's good to have a balance. I think this is better for Singapore, because no one way of governing will work in the current day and age," he added.

Many younger Singaporeans interviewed said they related to Mr Heng because they recalled his time as Education Minister.

In his four years at the ministry, he did away with school rankings, expanded assistance schemes for students in need, and shifted the system's emphasis from grades to talent, and from qualifications to skills.

Student Benjamin Wong, 23, said: "For people of my generation, he made an impression as Education Minister."

Mr Wong sees the public outpouring of concern when Mr Heng suffered a stroke in May 2016 as a signal of how well-liked he was by people, and a recognition of his contributions to the country.

The stroke had raised questions over his ability to weather the rigours of national leadership, but Mr Heng said on Friday that his doctors have given him "a clean bill of health", and that he would not have accepted the leadership of the party's 4G team if he was not confident that he was healthy.

His health is not an overriding concern for many, like Ms Chang Yen, 25, who feels Mr Heng is well-qualified for the job.

The communications professional said: "It's his experience and empathy that matter more."

Some Singaporeans acknowledged Mr Heng's strengths but wondered about possible shortcomings.

Researcher Aliff Faisal, 28, said the future PM would need more exposure so that citizens could get a clearer sense of him as a person and know what he stands for. "It would make him more relatable. He comes across as a soft-spoken, fatherly figure and a workaholic, honestly. And this combination seems to make him a dull person."

Businessman Ruben Ang, 59, felt that while Mr Heng's financial know-how is important for leading the country, his personality had to shine through more for him to connect with Singaporeans .

There were also some who felt Mr Heng's age could affect his staying power. Miss Shannon Chau, 27, a communications professional, said while Mr Heng has the experience to lead, she thought "they'd go with someone younger".

Mr Heng is 57, and Prime Minister Lee Hsien Loong has indicated that he plans to hand over by the time he turns 70, in 2022. Mr Heng will be 61 that year, making him the oldest person to become PM in Singapore's history should he eventually step into the role.

Mr Lee Kuan Yew became Singapore's first PM at age 35, in 1959. Mr Goh Chok Tong was 49 when he took the post in 1990. PM Lee was 52 when he took office in 2004.

But a party insider noted that age should not be a factor at a time when many regional and global leaders are advanced in age. Many Asean leaders are well into their 70s, and across the Causeway, Dr Mahathir Mohamad became PM again at age 93.

At the end of the day, Singaporeans told The Sunday Times that the question of which individual becomes the fourth prime minister does not really matter. The key is for the person to have the ability to lead and to have Singapore's best interests at heart.

Mr Tan, the temple volunteer, said the entire 4G leadership will be required to work together in order to lead Singapore effectively.

"It's always a team effort. So if he is able to work with the other ministers, then that is most important."

Mr Malcolm Kang, 37, a stay-at-home father of two children, said the Government is bigger than the individual, and the leadership of Singapore will boil down to how the entire government performs.

"I think who is in line to be PM doesn't really affect things, it's how the PAP and the Government conduct themselves," he said.

But identifying a leader, said freelancer C. Woo, 28, enables the country to move forward. "I'm very relieved that they have finally made a decision. To have no successor creates a lot of anxiety and uncertainty. Now we shall see if we can concentrate on cementing his authority."

• Additional reporting by Choo Yun Ting and Cheryl Teh