A hearing to determine the legality of opposition leader Kem Sokha’s pre-trial detention is scheduled to proceed on Tuesday, though it will likely take place without him in court due to “security concerns”, Prison Department officials confirmed yesterday.

Chan Kimseng, the chief of the General Prisons Department, raised concerns about “the security and safety during transportation” in a letter last Monday. As of yesterday evening, department officials had not yet announced whether or not the opposition chief would be shepherded from his Tbong Khmum province prison cell to the capital.

The Cambodia National Rescue Party chief was arrested this month on charges of “treason” in a case widely seen as political, and which has drawn international criticism. Sam Sokong, one of five defence lawyers, yesterday criticised the department’s request.

“If the hearing proceeds without Kem Sokha, we think that the decision by the Appeal Court will not provide justice to our client, and the hearing will not comply with international law and breaches the human rights of the accused,” he said.

Sokong added that lawyers would submit a motion today to demand Sokha’s presence in the court for the hearing, which will address the legality of the CNRP chief’s detention. They will then decide whether or not to boycott the hearing once the judge has ruled on the motion.

In a CNRP statement released on Saturday, the party claimed the purported security concerns were “just a pretext” to hold the hearing without their leader present and asked the court to respect legal procedures.

However, Prisons Department spokesperson Nuth Savna yesterday defended the prison chief’s request.

“We know that his supporters could organise protests during the hearing. And this would cause a problem in security control. We are afraid that a third person or anyone would have a bad intention to do something to the crowd,” he said. He added that such protests could also cause traffic jams and suggested the court could set up a video conference with Sokha.

Legal expert Sok Sam Oeun challenged the government’s explanation, however, saying there were ample means to protect the convoy and quell protests. “The government can use security forces to protect the court,” he said.

CNRP Deputy President Mu Sochua echoed this assessment, and added that having to resort to a video conference would be prejudicial against the defence. “That’s not an option at all,” she said. “He would still be in prison. How can he defend himself as a prisoner?”

Sokha was charged with treason on September 5 following a dramatic midnight arrest two nights before. The government has justified the arrest by pointing to a 2013 video in which the opposition leader said the United States government had supported him in building a political strategy.

Defence lawyer Sokong said his team would file motions this week requesting access to all remaining evidence, and will request to admit further evidence, such as the full version of Sokha’s allegedly incriminating speech. The defence will also request a summons of the person behind the anonymous Facebook account to which the incriminating video was re-uploaded.

In a letter to Secretary of State Rex Tillerson last Monday, eight US members of congress called for “all necessary diplomatic means” to compel Cambodia to respect the rule of law. “We are deeply disturbed by this pattern of constitutional abuse by the Cambodian government under the leadership of Prime Minister Hun Sen and the [Cambodian People’s Party],” they wrote.

In response to international criticism, Foreign Minister Prak Sokhonn defended the arrest before the UN on Friday.

“In what country would such behaviour of a foreign government be tolerated?” he asked. “Today we are accused of undermining democracy because, under existing laws, we are prosecuting and punishing people who violate these laws. Those who criticise us, even threaten us, refuse to take into consideration the crimes committed under the law by those whom they protect.”