PUTRAJAYA - Malaysian authorities have zeroed in on several individuals in the investigation into leaks of two papers in a national examination.

"These traitors have caused inconvenience to over 470,000 pupils and almost one million parents.

"I am sad because of the actions of these irresponsible individuals," The Star newspaper quoted Second Education Minister Datuk Seri Idris Jusoh as saying on Friday.

He said the culprits would face the maximum possible penalty.

He also told reporters that authorities have identified four "hotspots" but did not elaborate.

The education ministry announced on Wednesday that the Science paper in the UPSR examination, scheduled for Thursday morning, would be postponed to Sept 30 after the questions appeared on social media, local reports said.

UPSR is Malaysia's equivalent of Singapore's Primary School Leaving Examination.

A day later on Thursday, the ministry said the English paper - both paper 1 and 2 - was also leaked and students who sat for the exam in the morning will have to re-take the paper.

Idris had announced that pupils would have to retake the English Paper 1 and English Paper 2 on Sept 30, the same day as the Science paper.

He said no other papers in the UPSR have been cancelled, according to The Star.

A total of 473,175 pupils sat for the UPSR which started on Tuesday and was to have ended on Thursday. Vernacular school pupils were not affected as they sit for different English papers.

Idris said on Thursday that an independent committee would be set up to improve security measures. The aim of the committee would be to ensure that such leaks were not repeated and would comprise "high profile" members.

The minister also apologised to all the parents and pupils involved.