With Cambodia’s former opposition leader Kem Sokha languishing in a remote jail for more than three months now, international organisations and parliamentarians have renewed their calls for his immediate release and for the reversal of the controversial dissolution of his Cambodia National Rescue Party.

Under the aegis of the Asean Parliamentarians for Human Rights (APHR), 158 politicians from around the world yesterday sent an open letter to Prime Minister Hun Sen asking for Sokha’s release.

Sokha was slapped with a widely decried charge of “treason” over a 2013 speech in which he mentions receiving political advice from the US. His party – the only legitimate competitor to the long-ruling Cambodian People’s Party – was dissolved last month for allegedly fomenting a foreign-backed “revolution”.

“[T]aking note of the evidence submitted thus far by the government regarding his alleged guilt, we have serious concerns regarding the validity of the charges against him,” the parliamentarians’ letter reads.

They also called on the government to immediately “reverse the decision to dissolve the CNRP” and reinstate all CNRP leaders on all levels. The government has already moved to hastily redistribute the CNRP’s seats at the national to minor parties, and is preparing to reallocate the vast majority of its local seats to the CPP.

CPP spokesman Sok Eysan said APHR’s demands were an attempt to put pressure on Cambodia and to interfere in its internal affairs. “That stands in contrast to the Asean charter and the UN charter,” he said. “You should take a clear look at the constitution. Does the constitution of those countries [inform them they] control Cambodia or not?”

In their own letter to UN Secretary-General António Guterres, 42 ousted CNRP parliamentarians – including self-exiled former opposition leader Sam Rainsy – expressed on Thursday their concerns about the CNRP’s dissolution and the subsequent redistribution of its National Assembly seats.

“Contrary to the most fundamental principles of multiparty democracy, the seats have been stolen from those who were legitimately elected to them,” they wrote, asking for the 1991 Paris Peace Accord signatories to reconvene.

Forty-four of the CNRP’s 55 seats were given to three parties that, together, won less than 5 percent of the vote in 2013. The CNRP won 44 percent. The CNRP’s remaining 11 seats went to the CPP, which now holds 79 seats in the 123-seat Assembly.

Former opposition Deputy President Mu Sochua said free and fair elections, scheduled for July, could still take place if freedom of expression, assembly and the press were restored. “Our structure is intact; the people are determined to vote for positive change they have been waiting for [for more than] 30 years,” she said in a message.

Meanwhile, five pro-CPP Cambodian associations in Australia sent a letter to the country’s Senate and Parliament supporting the dissolution of the CNRP, ahead of planned pro-opposition protests there today.

“We reiterate once again that the resolution of the Supreme Court on 16 November 2017, was conducted in accordance with the laws of the Kingdom of Cambodia,” the letter reads.

Chan Pichra, deputy leader of one of the associations, maintained only a fraction of Cambodian-Australians were protesting. But Va Malina, one of the organisers of the pro-opposition protest, said he had never heard of the pro-CPP associations before and expected around 500 people.

Sochua, meanwhile, is slated to speak at a rally in front of Parliament in Canberra today before meeting with Minister of Foreign Affairs Julie Bishop.

According to Sochua, a petition will be submitted today to Bishop and Prime Minister Malcolm Turnbull calling for sanctions against the premier and high-ranking military officials.

Additional reporting by Ben Sokhean and Andrew Nachemson