New Zealander Graham Cleghorn - serving a 20-year prison sentence in Cambodia for rape - says he expects to be found guilty in the defamation case against him today.

"I'm going to stand up there and they're going to say `you're guilty, here's the sentence'," he told the Phnom Penh Post newspaper.

"Find me a case where a foreigner has been found innocent in Cambodia."

Cleghorn, 62, was sentenced by Siem Reap provincial court in 2004 to 20 years' prison for the rape of five girls aged between 14 and 19.

He is due to attend a verdict hearing late today (NZT) in the defamation case bought against him by the Cambodian Women's Crisis Centre (CWCC), which accused him of telling media outlets that the non-government organisation offered to pay each victim US$10,000 ($13,160) each to testify against him.

In a hearing last Monday, Mea Sophea, the lawyer representing the CWCC in Siem Reap, requested that the court demand Cleghorn pay US$5000 in compensation.

But in an interview with the Post at Prey Sar prison this week, Cleghorn, repeated previous statements that the case should never have made it to court.

"Apparently I'm not allowed to tell you that those people [the CWCC] are thieves and liars and set me up, because that's defamation now," he says.

"Any information I gave to the court [in prior hearings] is privileged information and can't be used against me in a defamation case."

But CWCC representative Say Vathany called the bribery claims "groundless".

"His defamation against CWCC is intended to discredit CWCC in a desperate attempt to influence a more favourable verdict for his case in the Supreme Court."

During the hearing last week, Siem Reap-based CWCC manager Ket Noeun said the defamation complaint stemmed from Cleghorn's repeated statements through the press.

Cleghorn has never denied making the claims in court, but denies making the claims in interviews to the press.

Cleghorn faces an extra two years in prison for each victim that he refuses to pay US$2000 in compensation to in relation to his rape conviction. He has said the money will go unpaid.

"I don't give a f... what they do," he said.

"I am what I am, and I am not going to pay these girls for lying. At least I can look in the mirror every morning and like what I see."

When asked if he would pay any compensation if he was found guilty of defamation, he grinned and said: "What do you think?"