Opposition figure Sam Rainsy formally called for a boycott of this year’s national election in the name of the now-dissolved Cambodia National Rescue Party on Saturday, though some former senior party leaders challenged his authority to speak on behalf of the opposition.

“Our decision not to go to vote essentially means we are voting in our hearts for the CNRP. We believe that, as an act of passive resistance, our decision to boycott the official election will help to peacefully put an end to dictatorship,” Rainsy’s statement reads.

He had previously made a personal appeal for a boycott, but party leadership had said an official call was still to come.

Rainsy was forced to step down from the CNRP after a contentious law banning convicted criminals from leading political parties was passed. The law was seen as personally targeting Rainsy, who has been convicted in a slew of politically tinged cases.

Then-Deputy President Kem Sokha took his place, but Sokha was arrested on widely decried charges of “treason” in September, with the CNRP forcibly dissolved shortly afterwards for allegedly fomenting “revolution” – a charge that went largely unsubstantiated.

“Only the CNRP, led by Sam Rainsy and Kem Sokha, has shown a reliable, clear and firm position in fighting for positive, democratic and peaceful change,” Rainsy wrote. He said any minor parties that partake in the “fake election” are merely “puppets” of Hun Sen’s regime.

However, Kem Monovithya, a former party official and Sokha’s daughter, said the party has not discussed a boycott yet. “CNRP leaders will meet in coming days to decide on our next steps,” she said in a message.

Sokha loyalist and former party official Ou Chanrath was more critical of Rainsy, saying he did not represent the opposition.

“Kem Sokha is still the party president. So what [Rainsy] appeals, even if it benefits the CNRP, it opposes the CNRP’s spirit because he is making decisions instead of the CNRP. It violates our rights,” Chanrath said.

In an email, Rainsy said he doubted that “CNRP leaders … or supporters would oppose my appeal”.

“What matters is the substance of my message and the resonance it finds with the Cambodian people. The rest is not important,” he said.

Mu Sochua, who was a deputy president of the CNRP at the time of its dissolution, threw her weight behind Rainsy on Sunday. “CNRM and CNRP call for boycott,” she said in a message.

“Boycott is a strong message that the next government without the participation of 3 million voters is illegitimate.”

While Rainsy may have officially left the party before its demise, he is “still very much a force to reckon with in Cambodian power politics”, said political analyst Lao Mong Hay.

“There simply is no politician outside the ruling party who is equal in stature to him,” he said.