While it's a good idea to have some kind of formal career guidance, I can see one difficulty. Teachers in Singapore are precisely that - teachers - and the majority of them don't know the working world, outside of the school environment. Thus they don't come with a wealth of career experience to share with their students (apart from a career in teaching).
My (mildly radical) suggestion is that schools heavily beef up their CCA programmes, and offer (1) a wider range of activities, and (2) more support and resources for each activity. The idea is to give students more room to explore their individual interests over a number of years.
This exploration is experiential - the student will actually do things, develop skills and have fun along the way. Through this process, the student gains some self-knowledge on the type of activities and environments (and by extension, the type of future career) that might appeal to him. Such self-knowledge, I believe, would go much deeper than what a student would most likely get out of a 30-minute, one-off session with a career counselor.
Many CCAs would not have a direct viable equivalent in the working world. Nevertheless the personal insights may be valuable. For example, as a student, my friend Adrian Tan joined the debating team and took part in many competitions. This eventually led him to choose a career as a litigation lawyer, where he makes a living by making arguments in court.
Another friend of mine (who shall not be named, because her current job is hush-hush) was the chairman / president type in school. She led various student committees in her secondary school, JC and university days. Now she holds a policy-making job within a certain government ministry, where she no doubt continues to lead her committees in her usual firm, no-nonsense style.
Some other examples. Joining a science club may help a student see whether R&D work would interest him. Joining the National Cadet Corps may help him to see whether a military career is a plausible option at all. Writing for a school publication may spark off an interest in journalism.
An art club may provide opportunities for students to test their interest in design-related jobs. Students involved in fund-raising projects may try their hand at marketing. The IT club allows students to see whether information technology appeals so much to them that they might one day pursue a career in it. And so on.
All of the above assumes that the student participates earnestly enough in his chosen CCAs, to gain such insights. It also assumes that the school allocates enough resources for the CCA activities to be carried out with some depth.