PHNOM PENH • Cambodia's Parliament amended a law yesterday to stop anyone convicted of an offence from running for office, effectively barring long-serving Prime Minister Hun Sen's main rival.

Critics said the changes approved will undermine the multi-party democracy established in the South-east Asian state by 1991 peace accords, and could turn the country into a de facto one-party state.

Under the changes, the Supreme Court will be allowed to dissolve any political party over the conviction of the party's top leader and ban its entire leadership from political involvement for five years.

Opponents accuse Mr Hun Sen, a former Khmer Rouge guerilla, of unfair manoeuvring to try to retain his three-decade grip on power at local elections in June and a general election next year.

The ruling Cambodian People's Party voted to change the 1998 election law to ban parties that engage in activities that include incitement, promoting secession, or anything that could harm national security.

Politicians convicted by a court are banned from standing for election and their parties can be dissolved.

That would exclude veteran opposition leader Sam Rainsy, who has been convicted of a series of defamation charges and has lived in exile in France since 2015.

He resigned from the Cambodia National Rescue Party (CNRP) this month, saying he wanted to save his party in the face of the potential ban. He rejects the charges against him as politically motivated.

The CNRP's 55 lawmakers boycotted the National Assembly vote yesterday, saying it targeted them. But Mr Hun Sen's party has a slim majority in Parliament, so it was able to pass the changes.

Welcoming the changes to the election rules, ruling party lawmaker Chheang Vun said they would allow the Interior Ministry to start closing some of Cambodia's 76 political parties. He said only 45 were properly registered.

The Asean Parliamentarians for Human Rights group called the law changes the "death knell for democracy" in Cambodia.

New York-based advocacy group Human Rights Watch said the changes marked the consolidation of absolute power.

"Cambodia will become a sham democracy going forward," said Mr Phil Robertson, the group's deputy director for Asia. "The silence of foreign governments and aid donors to this move has been profoundly disheartening."

Cambodia has been transformed during Mr Hun Sen's rule from what was essentially a failed state after decades of conflict.

REUTERS, XINHUA