Two other first-term parliamentarians, who were already acting ministers, were also promoted to full ministers on Wednesday.

Mr Jeffrey Siow, who was promoted to transport minister and second minister for finance, said it has been "a year of intense learning".

"PM has been very generous with his advice and counsel. Now and then, he would take me aside, have a quiet word with me every time that he sees that I can do better," said Mr Siow.

"This has given me the confidence for me to push forward, knowing that he is watching over our development, and also that we can count on his support."

Mr Siow, who was previously in the public service, said that "being a civil servant is very different from being a politician and being a minister".

He added: "I moved from being a product developer to really more of a product manager. There's a lot of explaining to people what we are doing, why we are doing certain things, and persuading people in the best way possible, in the most efficient way possible, in the most effective way possible what you're trying to do."

Mr David Neo, who was Chief of Army before joining politics, was promoted to minister for culture, community and youth and second minister for education.

"For this past year, my focus has really been to get down onto the ground, to engage all our local stakeholders, small groups at a time, 10, 15, sometimes one-on-one," he said.

This is to hear from them "how they experience our policies, what is working, what is not working, and more importantly, what are our common goals and objectives".

The most important political lesson has been to apportion enough time to listen to a diverse range of stakeholders, including arts and culture groups, heritage practitioners, community and religious groups, athletes and youth, he said.

Mr Neo, who drew some criticism recently for a remark in parliament that he made that ministers have no time to watch movies, was also asked for his response to this.

"Well, I should just not tell any more jokes," he said.

"As with all things, we all learn. And every time there's criticism, I take it positively as feedback, and it's just a matter of how things are experienced by different people.

"We look at it and then I ask myself, 'how can I do better going forward?' And that, I think, is the spirit in which I just keep taking in feedback."