Police are seeking the cabinet's go-ahead to wiretap criminal suspects without having to wait for the court's permission to speed up their investigations.
The request is believed to have support and backing from other security forces and the National Security Council (NSC).
A source at the Royal Thai Police (RTP) said Pol Col Kreangsak Chutiwut, chief of the Office of Legal Affairs and Litigation's legal affairs unit, had made the request to the cabinet.
The RTP wants an amendmet to Section 15 of the Criminal Procedure Code to allow police to eavesdrop on suspects, which police believe could help them expedite their investigations, the source said.
Winyat: Move could lead to abuse
Currently, officials require a court order if they want to intercept letters, postcards, publications and documents which are mailed or sent electronically.
The source said the law also applies to telephone use.
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Seeking evidence through wiretapping would help police keep up with fast-moving developments. Having to wait for court approval for eavesdropping could harm probes, he said.
"We are not asking for the power to carry out wiretapping in all cases," the source said, adding the RTP is demanding the ability to eavesdrop in four cases -- terrorism, transnational crimes, security cases and complex crimes with a statue of limitations of at least three years.
Police said the Department of Special Investigation (DSI) has authorisation to eavesdrop based on the act governing the agency, but police still have no such power, the source noted.
A source attached to the Crime Suppression Division said without the law change, police surreptitiously ask for phone records from telecommunications service providers as part of criminal probes without seeking court approval.
Coming up with laws to legitimise the approach would help ensure the investigation is done lawfully and protect officers who are performing their duties, the source noted.
"This is a matter of bringing something underground up to the surface," the source said. "The laws would make police work easier."
The move, however, could spur concerns about violations of privacy rights, according to observers.
Complex crimes with a statue of limitations of at least three years are broad and cover almost all criminal offences, the observers said. Pol Col Kreangsak reportedly told his police associates the request still has to undergo a long process.
By authorising security forces to wiretap criminal suspects, the cabinet would be approving violations of citizens' right to privacy, says human rights advocate Winyat Chatmontree.
Mr Winyat, who has handled terrorism and security offence cases, said the definition of those crimes, or that of a "criminal suspect", may be subject to wide interpretation.
Previously, authorities were only permitted to wiretap individuals who had been formally accused during an investigation. However, the amendment will permit security forces to wiretap practically anyone they consider dubious, he argued.
Without the need for a court mandate, he said officers would have unchecked powers, which could lead to abuse.
"The court acts as a guardian of the public interest," he said. "If this step is bypassed, who will be able to scrutinise the work of the security forces?"