Crawford Brown, 24, a student from the University of the West of Scotland, spent the weekend in jail after being pulled over by police for riding naked.
Police also caught 22-year-old Catarina Aarnio, from Finland, and Italian Giancarlo Allocca, 30, travelling naked with Mr Brown.
Officer Chuon Chomkol told the Cambodia Daily: 'We saw them drive in front of our commune police station and I then ordered my officials to follow them and stop them.
'They drove when they had no clothes on. It looked so indecent in public and in our country, so we needed to arrest them.'
He added: 'I can't let foreigners act like this, even if they didn't know the traditions of our country.'
He said the backpackers did not immediately stop when police gave chase as they were not aware they had done any thing wrong.
He believed the naked trio were planning to cross a border checkpoint in to Vietnam.
Kandal police chief Eav Chamroeun told the Phnom Penh Post: 'I think that this was the first time there have been foreign people driving motorcycles naked in Cambodia.
'Their actions have seriously violated Cambodia's integrity, the beautiful customs and culture of Cambodia, and Cambodian law. We cannot allow them to commit pornography like this in our country.'
'The General Department of Immigration has asked the leadership of the Ministry of Interior to expel them from the country as punishment,' Sok Phal, head of the Ministry of Interior's immigration department, said.
It was reported they would be permanently barred from the country for violating a section of the Penal Code related to indecent exposure.