The new ministers and senior ministers of state in the latest round of Cabinet changes will be core members of Singapore's fourth-generation leadership.

Their promotions are in line with the practice of testing younger ministers in various areas, to stretch them and expose them to new challenges.

Mrs Josephine Teo and Mr Desmond Lee were promoted to full ministers, and while they do not helm their own ministries, they continue to hold key portfolios. Mrs Teo is in the Foreign Affairs and Manpower ministries, while Mr Lee is in the Home Affairs and National Development ministries.

Over the weekend, Prime Minister Lee Hsien Loong said both have done good work and shown they are capable of more responsibilities. He expects them to do even more. PM Lee also expects to do a much bigger set of changes next year, and said more new ministers will helm their own ministries.

At the May Day Rally yesterday, he also said that younger ministers will be in charge of Singapore's next phase of economic development.

They will work together in the Future Economy Council to oversee skills and innovation. "It is this generation of leadership who will have to work with Singaporeans to take this country to new heights."

By making sure promising ministers can thrive in various portfolios, Singapore's political leadership avoids putting all its eggs in one basket.

As Institute of Policy Studies deputy director Gillian Koh puts it, the Cabinet "is not going to be dependent on just one person for just one thing".

Additionally, double-hatting exposes younger ministers to more issues in half the time.

Dr Lam Pin Min, Dr Janil Puthucheary, Dr Koh Poh Koon and Mr Chee Hong Tat were also made senior ministers of state in their current ministries. Dr Lam was given a second portfolio, transport.

The exposure means the ministers of tomorrow will be experienced hands better equipped to deal with increasingly complex issues such as an ageing society and a more challenging economic landscape.