And she was promoted to become a minister because of merit, not gender, he added.

Mrs Lim, 50, the Senior Minister of State at the Finance and Transport ministries, will become Second Minister in both ministries as well as a Minister in the Prime Minister's Office (PMO) from Wednesday.

Said Mr Lee: 'We can't take her out from these two ministries now, but I will consider her to head a ministry on her own if she continues to perform well, which I'm sure she will, and when the opportunity arises.'

He added that she is fully engaged at the two ministries and her being placed in the PMO is 'a technicality because she is a full minister'.

He pointed to labour chief Lim Swee Say as another example of a full minister placed in the PMO but whose responsibilities are elsewhere.

In Mr Lim's case, they are at the National Trades Union Congress, where he is the labour movement's secretary-general.

Mr Lee said that Transport Minister Raymond Lim has told Mrs Lim she will be responsible for maritime and aviation issues at the Transport Ministry.

Asked if Singapore would see more women ministers, he said: 'Well, I hope we will have more female ministers. If you look at the Parliament, we've had more female MPs. I hope that among them, there will be more potential office holders and in due course more ministers.'

Read the full report in Tuesday's edition of The Straits Times.