"We hope the police will take firm action and bring to book the culprits who must be severely punished," he told a press conference here.
Muhyiddin, who is Education Minister, said the leaks could also have been purposely done to sabotage him personally and the Education Ministry.
He said he was not making any assumptions as to who might have done it but wanted the police not to rule out this angle.
Muhyiddin, who is here to attend the 8th Asean Education Ministers Meeting, was visibly upset about the latest leaks in the UPSR Bahasa Inggeris 014/1 and 014/2 papers today following the detection of leaks in the Science 018, 028 and 038 papers.
The Examinations Syndicate has announced pupils would have to resit all the leaked papers on Sept 30.
Muhyiddin said an independent committee comprising examination experts would be set up soon to manage public examinations to ensure integrity and confidentiality of examination papers.
He said he was extremely dissapointed that such leakage happened more so when he had reminded the parties responsible to observe all regulations and procedures to prevent such a thing from happening.
This had not only called into question the integrity of the ministry but also make it look as though it did not know how to handle examinations, he said.
"Those who did this (causing the leaks) should know the UPSR is to test the competency of our children and the consequences of their action.
"I can understand the feelings of the parents and the pupils themselves who will have to resit the papers," he added.
He said he did not want to assume officers of the Examinations Syndicate were involved but the police must go after the mastermind involved in leaking the papers on social media.
As the minister responsible, he said he apologised once again (after having apologised over the leak in the science papers) to the parents and pupils over the stress they have to go through.
He added that he would be meeting the Examinations Syndicate as soon as possible to discuss ways to improve confidentiality of examination papers right from the time they were prepared until they were handed out to the pupils during examination days. - Bernama