Considering it could be a year or more before a vaccine for Covid-19 is found and since there are few new cases of infection in the community, now is a good time to reopen schools, Education Minister Ong Ye Kung said yesterday.

Extended closure of schools would have a tremendous impact on children not just in academic terms, but also emotionally and socially, he added.

"We must remember, education is really not just about taking exams or getting good grades," said Mr Ong.

"It is (also) about the character and socio-emotional development. And we cannot deprive a whole generation of that experience."

The Ministry of Education (MOE) will be reviewing ways to blend classroom and digital learning to "harness the best of both worlds in a modern education system", he added.

Self-directed learning cannot fully substitute in-class learning, but it can give children the time and space to explore and study at their own pace, Mr Ong noted.

It also allows them the opportunity to satisfy their curiosity and go beyond the curriculum.

Mr Ong was speaking to reporters during a visit to Xingnan Primary School in Jurong West yesterday, as schools across Singapore opened their doors to welcome back some 250,000 students from selected cohorts.

"(We will) come back to school progressively, with precautions, and make things as safe as we can."

During his visit, Mr Ong spoke to pupils arriving at school in the morning and joined a class for morning assembly, which was held in the classrooms.

Each cohort took its own route to get to its classroom.

The pupils also had designated toilets.

Mr Ong also visited a Primary 6 class' physical education lesson, which was conducted in the school hall by a teacher wearing a face shield and using a microphone.

Pupils were taught how to remove their masks and place them into resealable bags to be stored and worn again after the lesson.

Mr Ong later joined a group of Primary 5 pupils for recess.

Across schools, daily face-to-face classes will be conducted only for the graduating cohorts of Primary 6 and Secondary 4 and 5.

Those in Primary 4 and 5 and Secondary 1 and 2 were also at school yesterday, but they will rotate weekly - with students from the remaining batches - between home-based learning and having lessons in class.

Up to 50 per cent of students in junior colleges and Millennia Institute (MI) returned to their schools as well, with priority given to graduating students.

The attendance rate for the selected cohorts yesterday was 97.6 per cent for primary schools, 97.7 per cent for secondary schools and 98.4 per cent for the JCs and MI, which MOE said is "healthy".

All schools will continue with tightened safety measures, such as students staying in class groupings, fixed exam-style seating and appropriate distancing.

Staggered recess times and dismissals, daily temperature taking and wipe-down routines will continue, with new rules such as having teachers and students wear face masks or face shields except when eating and exercising.

Primary 6 pupil Sophia Wu, 11, said she is not used to donning a mask most of the time.

"It is suffocating because you can't really breathe well and it makes you warmer," she said, but she added that she and her classmates have been able to cope with the safety measures so far.

Xingnan Primary School principal Charles Chan said the school is trying to find ways to motivate pupils to adhere to the measures.

For example, it has extra masks from its school uniform vendor and could allow the children to decorate these themselves.

Said Mr Chan: "If they personalise their masks, put buttons or ribbons or perhaps their names, they will own the masks and perhaps they will want to use them more - a new accessory for them that will be part of life and the 'new normal'."