MANILA (UPDATE) - President Rodrigo Duterte has signed a law giving subpoena powers to the Philippine National Police (PNP) chief and other select police officials, a measure seen to speed up criminal investigation.

Duterte signed on March 1 Republic Act 10973, which amends Republic Act 6975 or the Local Government Code.

Under the revised law, the PNP chief and the director and deputy director for administration of the PNP-Criminal Investigation and Detection Group “shall have the power to administer oath, issue subpoena and subpoena duces tecum (documents) in relation to its investigation.”

President Duterte has signed a law granting subpoena powers to the PNP chief | via @dgplacido pic.twitter.com/3PlUHAbP5A

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A subpoena is an order that requires a person to appear before a court or a body, while a subpoena duces tecum requires a person to produce a certain document or item which may be vital to a case or an investigation.

According to the law, the subpoena powers given to the three high-ranking PNP officials “shall be exercised solely by the aforementioned officials and may not be relegated to any other person or office.”

The subpoena should also state the nature and purpose of investigation, and be directed to the person whose attendance is required. In the case of a subpoena duces tecum, it should contain a reasonable description of the books or documents being sought.

“Failure to comply with subpoena and subpoena duces tecum shall authorize the filing of a case for indirect contempt under the Rules of Court with the Regional Trial Court,” the inserted provision reads.

Sen. Panfilo Lacson, who authored the bill, said it only made sense for the CIDG, being the police’s primary investigative unit, to have subpoena powers.

The PNP had been the only law enforcement agency without subpoena powers, as the Department of Justice, the National Bureau of Investigation, and the Philippine Drug Enforcement Agency have long held such authority.

Human rights lawyer Edre Olalia, meanwhile, called the move "unwarranted, unnecessary and dangerous."

"Unwarranted because it gives a component of quasi-judicial powers to an agency primarily tasked with law enforcement (which leaves much to be desired). Unnecessary because there are more than enough agencies empowered to issue subpoenas," Olalia said in a statement.

"Dangerous because given the spotty record, low credibility and non-professional loyalties of police heads, this power gives additional tool for abuses and excesses against the public," he added.

Bayan Muna Rep. Carlos Zarate echoed Olalia's sentiment and said he fears that the law would "grant additional powers to the PNP-CIDG that can potentially be subjected to abuse and further human rights violations."