The Cambodian prime minister has vowed to beat up protesters if they burn effigies of him at a summit of Southeast Asian leaders in Sydney next month.

Hundreds of Cambodians living in Australia are expected to rally against Hun Sen when he attends the Australia-Association of South East Asian Nations summit in mid-March.

Cambodia's democracy is under attack, with the country's Supreme Court dissolving the Cambodia National Rescue Party last year and jailing opposition leader Kem Sokha.

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"I want to remind those who plan to demonstrate against me that my visit is an honour for their government," Prime Minister Hun Sen said in a speech, according to translated subtitles.

"If they burn my effigy ... I will pursue them to their houses and beat them up."

An Australian filmmaker James Ricketson is in jail in Cambodia, facing spy charges after flying a drone over a political protest in the capital Phnom Penh last June.

He faces five to 10 years behind bars if convicted.

Last week, exiled former Cambodian opposition leader Sam Rainsy said Mr Ricketson was a scapegoat and his arrest was designed to frighten and deter foreign journalists from writing critical reports of Hun Sen's government.