The president of an international umbrella group of liberal political parties has lent his support to a recent International Criminal Court complaint asserting the Cambodian government and government-connected elites are guilty of crimes against humanity for their involvement in “widespread and systematic” land grabbing.

Juli Minoves Triquell, president of Liberal International (LI), which counts the opposition Cambodia National Rescue Party as a full member, urged the court on Thursday to investigate the complaint, saying it was precisely the type of case the court was designed to hear.

“As an international institution dedicated to ending impunity for the perpetrators of the most serious criminal acts, the ICC must investigate these allegations of crimes against humanity,” Minoves Triquell said in a statement.

The former diplomat, who signed the statute establishing the ICC on behalf of his native Andorra, went on to add that “this is a case cut out for the ICC; the whole bureau of LI at our last meeting in London decided to support this quest for truth and justice”.

The ICC communication, filed on October 7 by attorney Richard Rogers on behalf of 10 victims, contends members of the government and their associates in business “carried out an attack on the civilian population with the twin objectives of self-enrichment and preservation of power at all costs”.

Government spokesman Phay Siphan said the complaint was a ploy by the CNRP, which first invited Rogers to investigate the alleged crimes, but which is not officially tied to the communication.

“Who supports whom? They have their own interests,” Siphan said, maintaining that the ICC communication was “initiated by [CNRP deputy president] Kem Sokha’s daughter”.

“I leave this open to the ICC to determine if this [complaint] is enough” to warrant investigation, Siphan added.

Sokha’s daughter, CNRP deputy public affairs head Kem Monovithya, has insisted she had no role beyond “connecting” Rogers to alleged victims.