Daniel Jones, on trial for promoting a pool party with images deemed "pornographic", is escorted by a prison guard at a court in Siem Reap on March 15, 2018. Image Credit: AFP

SIEM REAP, Cambodia: A British expat facing up to a year in Cambodian prison for promoting a pool party with images deemed "pornographic" apologised during a court hearing on Thursday, saying he did not know the advertisements breached an indecency law.

Daniel Jones, 31, was among 10 foreigners arrested in January after police raided their pool bash at a private villa in Siem Reap, a popular hub for tourists near Cambodia's famous Angkor Wat temple ruins.

A Siem Reap court ultimately dropped charges against the others but has pursued a case against party organiser Jones, who has been held in jail for nearly two months and is accused of producing pornographic materials to promote the party.

In the trial's first hearing on Thursday Jones admitted to advertising the "Let's Get Wet" event on Facebook with images from a previous pool party.

He insisted that there was no nudity or sex involved, but apologised for offending Cambodian people.

"Now I understand in Cambodia that these pictures are not good," he told the court, adding that he did not take the photos himself.

Prosecutor Seng Samnang said any images that encourage sexual activity are illegal and against Cambodian culture.

"I did not understand Cambodian law. I am very sorry for that," Jones responded.

A police witness said during the trial that cops raided the party to prevent acts of sex, adding that they found some condoms at the villa.

Jones said he had organised a total of four parties for tourists before his arrest, charging attendees $5 for transportation, a free drink and T-shirt.

When a prosecutor showed him images he was accused of spreading on Facebook, Jones said that most belonged to a different event group - known as "Pub Crawl" - which had been shut down in November.

No date has been set for a verdict.

While Cambodia is a popular with foreign "backpacker" tourists and boasts a free-wheeling nightlife, the Buddhist country is often strict when protecting local traditions or heritage sites.

Authorities banned skimpy clothing inside the Angkor Wat complex in 2016 and have previously deported foreigners for taking racy photos among the temple ruins, which are considered sacred.

But the location of those violations was inside the ancient city, not in the adjoining town of Siem Reap, a popular party destination lined with bars catering to foreigners.

Defence lawyer Suong Sophea urged the judge to consider the impact on tourism when penning a verdict for Jones.

"If such activities are considered offences, it will affect the tourism in Cambodia," he said.