An Australian filmmaker, who was accused of being a spy and found guilty in Cambodia, has questioned the conviction based on the evidence and facts provided in court.

James Ricketson, who is 69 years old, has been sentenced to six years in the country's notorious Prey Sar prison. He had been facing a maximum ten year term.

Earlier, he had arrived at court in a prison van, telling journalists, "I hope I am free today and could go home."

Australian filmmaker James Ricketson has been sentenced to six years in a Cambodian jail for spying. (AP/AAP)

As the prison van left after the panel of judges delivered the verdict however, Ricketson shouted to reporters the same question he often raised throughout his trial: "Who am I spying for?'"

Ricketson was arrested in June last year after flying a drone over a political rally held by the Cambodia National Rescue Party, which opposed the Government in the lead up to recent elections.

The drone was recording footage Ricketson wanted to use as part of a documentary about the country's street kids.

The 69-year-old was facing a maximum 10 year sentence and had voiced his hopes for freedom before the verdict was handed down. (AAP)

The Cambodia National Rescue Party was dissolved as part of a crackdown on opposition and any media who were critical of Prime Minister Hun Sen's government. Sen's ruling party won all 125 seats in the National Assemby.

Prosecutors believed Ricketson was sympathic to the opposition party, and so tried him on the basis of espionage, because the government claimed Ricketson's material could compromise Cambodia's national security.

The filmmaker however has repeatedly insisted he had no political agenda and his work making documentary films was journalistic in nature.

Ricketson was arrested in June 2017 after flying a drone over a political rally held by the Cambodia National Rescue Party, which opposed the current national government. (AAP)

Prosecutor Seang Sok said Ricketson had entered Cambodia to incite hatred, however, it was never specified which foreign power he allegedly spied for.

The evidence presented in court against Ricketson appeared thin, but included a handful of personal emails seized from him.

The emails suggested he was sympathetic to the country's political opposition and critical of Hun Sen's government, but revealed no sensitive or secret information.

Several of his photos and videos also showed security forces on duty, but only in publicly viewable situations.

As the prison van left court, Ricketson was heard shouting to reporters 'Who am I spying for?' (AAP)

Prosecutors in the case had indicated Ricketson also was suspected of working with the opposition Cambodian National Rescue Party, which for a time had enough popularity among Cambodians to be a viable challenger to Hun Sen's rule.

Ricketson's son, Jesse, told reporters in Cambodia today that the verdict is "absolutely devastating" for their family.

"The human toll of this situation is really hard for everyone," he said.

"This result will send shockwaves out through all of our family and our community and all of James's supporters and it's a really long, hard road to this point and now to get this result is just heartbreaking.

Ricketson's son, Jesse, told reporters in Cambodia that the verdict for his father has left his family 'devastated'. (9NEWS)

"I feel so much for my father right now, he'd be feeling it really strongly and who knows what comes next."

Ricketson's nephew, Bim, also told reporters in Sydney today that the verdict is "completely mad".

"He loves Cambodian people. He goes there regularly - has done for 22 years, capturing the lives of the poor people there and helping them," he said.

"For that to be interpreted somehow as espionage is completely mad."

The filmmakers nephew, Bim, also said that for his love of Cambodia to be interpreted as espionage by the Cambodian government is 'completely mad'. (AAP)

Australian Prime Minister Scott Morrison today said the Federal government is offering all the support it can to Ricketson.

"Foreign minister Bishop at the time had made some direct approaches about that issue and represented Australia's view at the time (he was arrested," he said.

"He can expect to get all the consular and other support from the Australian government you'd expect in these circumstances.

"In these types of events, it's best to deal with these things calmly and directly and in a way that best assists a citizen."

Australian Prime Minister Scott Morrison said the Federal government is issuing as much support as it can to a citizen in Ricketson's position. (9NEWS)

Ricketson has been visiting Cambodia for more than twenty years, where he has produced documentaries and blogs about the country's underprivileged people.

He has been critical of PM Hun Sen, who has ruled Cambodia with an iron fist for more than three decades.

In his defense, Ricketson testified that he made contacts with the opposition party strictly for journalistic purposes while making a documentary film.

He recounted a filmmaking career dating to the 1970s, and presented acclaimed Australian movie director Peter Weir to attest to his professionalism in the field.

The filmmaker has been consistent in denying the validity of the conviction and said he was never acting with a political agenda. (AAP)

Ricketson's other character witnesses were several Cambodians - including his informally adopted daughter - who described how he had provided financial assistance to them and other poor members of Cambodian society.

Throughout his trial, Ricketson shouted brief but defiant remarks to reporters as he was led in and out of the court building for each hearing.

He decried the paucity of evidence and repeatedly asked the taunting question of what country he was supposed to have been spying for.

In recent weeks Ricketson suffered several health problems including skin, chest complaints, and had to be treated in the prison hospital.