Prime Minister Hun Sen has called on
Mr Hun Sen also warned that the CNRP could be dissolved if the opposition party tried to defend Mr Sokha.
CNRP President Mr Sokha was arrested in the early hours of Sunday on allegations of treason and was sent to be detained in a prison in Kbong Khmum province, which is about 80 kilometres from Phnom Penh.
He was arrested after video footage from the Australia-based CBN news was posted on Facebook in which Mr Sokha told his audience that the US government had been helping him to change the government in Cambodia since 1993.
Speaking in a meeting with workers on Sunday, Prime Minister Hun Sen said Mr Sokha had betrayed his country and had worked with foreigners to make regime change.
“This issue is very serious,” he said, adding that police would not have made the arrest if it had been a small issue.
He added that Mr Sokha had confessed that the US helped him and used academics and others to plan the change of government.
