All pupils and staff of Punggol Primary School are undergoing mandatory swab tests over two days from yesterday.

This comes after a new cluster linked to a cleaner at Punggol Primary School was identified on Tuesday and grew to 12 cases as at yesterday, according to the Ministry of Health.

Meanwhile, the school switched to home-based learning from yesterday to Aug 6.

In response to queries from The Straits Times, the Ministry of Education (MOE) on Wednesday night gave details of six of the cases in the cluster.

It said one teacher and two pupils have tested positive.

The teacher is not a close contact of the pupils, and investigations are under way to see if the cases are linked.

Another two contract cleaners and one member of the school's non-teaching staff have tested positive for Covid-19. The trio had not been in close contact with pupils and teachers.

All close contacts of confirmed cases have been placed under quarantine order or leave of absence, said MOE, adding that the school has also been thoroughly cleaned and disinfected.

MOE said it will continue to monitor the situation closely, and work with the school and parents to ensure the well-being of staff and pupils.

The ministry added: "Students and staff should also seek medical attention immediately if they feel unwell. Continue practising good personal hygiene and adhere to safe management measures."