A ship carrying 41 Chinese nationals capsized off the coast of Cambodia Thursday evening, leaving 23 people missing, Cambodian authorities said.

The vessel reportedly sank near port village Sihanoukville on September 22, provincial spokesperson Kheang Phearom confirmed on Friday.

Eighteen people have been rescued while 23 more remain missing.

A representative of the group reportedly told police they had left China's Guangdong province by speedboat on September 11.

With the help of two Cambodian personnel, they then allegedly transferred to the ship about a week later, but it had begun to sink when they reached Preah Sihanouk waters, provincial police chief Chuon Narin said.

The Cambodian nationals were reportedly fetched by a fishing boat before the vessel capsized, he added. The pair have been captured and detained for interrogations.

Authorities said they are still questioning the rescued individuals, who are suspected of being trafficked into Cambodia.

Sihanoukville has recently seen an influx of Chinese investments, sprouting dozens of gambling sites - which allegedly hire smuggled workers - in the fishing town.

Cambodia has launched nationwide immigration checks on foreigners living in the country, which has become a hotbed of trafficking for migrants scammed by the promise of lucrative jobs, only for them to become slaves in boiler room call centres, illegal casinos, brothels and other underground enterprises.

Last August, footage emerged of Vietnamese workers jumping into a river in Cambodia's Kandal province to escape from a Chinese-operated casino.