Civil rights group Article 19 has urged the authorities to cease the crackdown on social media users.

"Article 19 is concerned about the arrest and remand of two unnamed social media users and the ongoing police search for a further two social media users in the space of just two days, for comments made on Facebook.

"We urge the Malaysian government to immediately release both individuals who are currently held in police custody and who have been further remanded for investigation under Section 117 of the Criminal Procedure Code, and to cease all other arrests and investigations of individuals targeted for expressing their opinions.

"This is part of a broader trend that must end," it said in a statement.

Article 19 said the arrests represented a violation of individuals' right to freedom of expression.

A man was arrested on April 10 over a photograph of himself holding a banner deemed to have maligned the government, which was posted on Facebook.

The following day, another social media user was arrested for allegedly insulting the Johor Sultan on Facebook.

Police are also tracking down two more individuals who allegedly insulted the Terengganu Sultan on Facebook.

The cases are being investigated under Section 233 of the Communications and Multimedia Act (CMA) 1998 as well as Section 505(b) of the Penal Code.

Section 505(b) of the Penal Code makes it a criminal offence for “whoever makes, publishes or circulates any statement, rumour or report with intent to cause, or which is likely to cause fear or alarm to the public, or to any section of the public whereby any person may be induced to commit an offence against the State or against the public tranquillity”.

Section 233(1)(a) of the CMA makes the “improper use of network facilities or network services” a criminal offence.

Article 19 had previously highlighted the need for Section 233(1)(a) to be revised to more narrowly and precisely define what constitutes an improper use of network facilities and services.

It said the current wording creates an overly broad content-related offences on top of a lack of adequate safeguards against censorship.

"Article 19 reiterates our concerns over the arrest and detention of the aforementioned individuals and calls for all investigations to be dropped and for the immediate release of both individuals.

"Article 19 also calls on the government to protect the right to freedom of expression, which is guaranteed under Article 10(a) of the Federal Constitution, and to ensure that all existing laws that limit the right to freedom of expression are repealed or amended to fully comply with international standards.

'This requires the repeal of Section 505(b) of the Penal Code, and the reform of relevant provisions of the CMA, including Section 233(1)(a)," it said.