International human rights and labour rights organisations have written an open letter to Cambodia's Prime Minister calling for the release of 23 workers arrested during wage protests last month.

A brief rally is understood to have taken place outside the Ministry of Justice and the Appeals Court in Phnom Penh today (10 February), where around a dozen protesters demanded freedom for the activists and workers arrested last month during a crackdown on striking workers.

In December, garment workers walked out in a mass call for the minimum wage to be doubled from US$80 to $160. Escalating violence against the protesters led to the deaths of at least four people in early January, the arrest of 23 workers, and the dismissal of hundreds more.

Unions and associations have since been urging the release of the arrested workers, with around a dozen organisations, including The International Federation for Human Rights (FIDH) and the International Labor Rights Forum (ILRF) today adding to the calls.

In the letter, the groups ask Sen to "immediately and unconditionally" release all detainees and to drop all cases against those being investigated in connection with the protests.

They also want "appropriate legal action" to be taken against companies that have fired or punished workers and union members "in retaliation for their exercise of basic human rights".

"The Cambodian government's detention of activists and ban on protests are generating intense public concern not just in Cambodia, but around the world," said Phil Robertson, deputy Asia director at Human Rights Watch. "Governments concerned about the basic rights of the Cambodian people should also make their voices heard."

The groups also expressed "extreme concern" that Cambodian authorities have suspended public assemblies, in violation of international law.

The organisations have called on Sen to "promptly revise all laws, decrees, sub-decrees and decisions containing provisions that restrict the rights to freedom of peaceful assembly, association and expression, including rights related to union activities, to bring them into accordance with international human rights law and best practices".

It is understood the Appeals Court is set to hear bail requests for the remaining detainees tomorrow.