A Cambodian court on Thursday jailed a woman union leader for two years for leading a strike against the country's biggest casino to demand the reinstatement of workers laid off during the pandemic.

Chhim Sithar had long campaigned for the return of hundreds of workers laid off from the NagaWorld casino in Phnom Penh.

She was first arrested in January last year at a protest site near the casino and was charged with incitement, a common tactic authorities use against activists.

Chhim Sithar was re-arrested in November for violating bail conditions upon her return from a conference in Australia.

Several dozen former casino workers protested outside the court after her sentencing on Thursday, shouting "injustice" as Chhim Sithar was taken away in a prison van.

Rights groups have said the charges are baseless.

Five other union members from her group were given 18-month court monitoring orders and three more received one-year suspended jail sentences.

Prime Minister Hun Sen -- who has ruled Cambodia for backlink more than 38 years -- has been accused by rights groups of using the courts to stifle dissent as he prepares for the July election.

Nagacorp -- a Hong Kong-listed firm that operates NagaWorld -- has an exclusive casino licence to operate in Phnom Penh.

Cambodia has a complex relationship with gambling: while it has casinos, its own citizens are officially barred from playing in them.