Malaysia's Human Rights Commission Suhakam said it will proceed with a public hearing on the disappearances of a Malay Christian pastor, his wife and a social activist, a day after abruptly halting a separate inquiry into missing pastor Raymond Koh.

The cases of the four missing Malaysians are closely watched because police have been unable to provide answers on their whereabouts after months of investigations.

There is also some concern among non-Muslim minority groups that the missing persons could have been abducted by Muslim vigilantes amid the rise of an intolerant strain of Islam in Malaysia.

Suhakam's hearing on Mr Koh was stopped on Tuesday after police told the commission that the case has become a legal issue for a court to decide, after a suspect was charged in the pastor's case.

Mr Koh was abducted in Petaling Jaya on Feb 13 last year.

Mr Joshua Hilmy and his wife Ruth were reported missing by a close friend on March 6 last year.

Social activist Amri Che Mat, founder of non-profit organisation Perlis Hope, was allegedly abducted on Nov 24, 2016.

His vehicle was found abandoned nearby.

There has been media speculation that he was promoting Shi'ite ideology, a branch of Islam that conservative Malaysian Muslims reject. Mr Amri's wife has denied the claimed link to Shi'ism.

"The next hearing date is scheduled for Jan 22. We will look into the circumstances of Amri Che Mat's disappearance," Suhakam commissioner and panel chief Mah Weng Kwaisaid at a press conference yesterday.

Mr Koh's wife Susanna Liew yesterday issued a statement to say if the suspect charged in court is someone actually linked to the kidnapping, "then the whole world will be watching this case very closely to scrutinise what the police will do about this going forward".

The four missing people have been the subject of a hearing since October by the rights commission.

Suhakam in recent weeks had been focusing on police investigations into Mr Koh's case.

The 11-day inquiry had revealed details of the kidnapping, which witnesses said appeared to be executed in minutes with professional precision.

Closed-circuit television footage believed to be from the scene of the incident showed half a dozen men in balaclavas blocking Mr Koh's car with black SUVs on a public road in Petaling Jaya in broad daylight.

Lam Chang Nam, 31, was charged last March with extorting RM30,000 (S$10,000) from Mr Koh's son, Mr Jonathan Koh Szu Hao, in exchange for his father's release. Malaysian police chief Mohamad Fuzi Harun said in a statement on Tuesday that Lam has now been charged with kidnapping.

"Investigations are still ongoing and we have found a new lead that associates Lam with Koh's abduction," the statement read.