Australian filmmaker James Ricketson has been found guilty of espionage and sentenced to six years in a Cambodian prison.

Key points: After the verdict, Ricketson asked "which country am I spying for?"

After the verdict, Ricketson asked "which country am I spying for?" Ricketson's family are concerned for his health and have called on the Australian Government to intervene

Ricketson's family are concerned for his health and have called on the Australian Government to intervene He has 30 days to launch an appeal

A trio of judges ruled Ricketson, 69, had for more than 20 years used documentary projects and humanitarian work as cover while collecting information that could jeopardise Cambodia's national security, despite a prosecution that offered little evidence to support the charge.

When the verdict was delivered shortly after 10:00am (local time), Ricketson turned to the gallery and asked a question that has thus far gone unanswered: "Which country am I spying for?"

Then, from the window of the prison van taking him away from court, Ricketson cried out again: "Who am I spying for?"

James Ricketson has been sentenced to six years in a Cambodian prison. ( Supplied )

The case against Ricketson amounted to a series of photographs and emails taken from his computer, which the prosecution presented as evidence he came to Cambodia with the "intention to incite hatred".

Ricketson was arrested in June last year, a day after he was reprimanded by authorities for flying a photographic drone without permission over a political rally.

Soon after, government-friendly media outlets named him as an "important spy" in a US-led plot to foment a "colour revolution" and overthrow Prime Minister Hun Sen, who has ruled Cambodia for more than 30 years.

Neither the US nor Australia have made a public statement distancing themselves from Ricketson.

Ricketson and his family have called for more support from the Australian Government. ( Supplied: Jesse Ricketson )

The accusations against Ricketson came amid a spate of politically-charged moves by Hun Sen's Cambodian People's Party, which was facing perhaps the greatest threat ever to its three-decade rule.

Independent media were shut down and journalists jailed, non-government organisations were ordered out of the country, and the surging opposition party was dismantled and its leader sent to a remote prison following a midnight raid on his home.

Then, last month, with almost all voices of dissent vanquished or paralysed by fear, Hun Sen's Cambodian People's Party secured all 125 parliamentary seats in an election that was widely slated as a "sham".

Family in 'utter shock', says 'James is not a spy'

Jesse Ricketson has moved to Cambodia so he can visit his father James Ricketson in prison. ( Supplied: Jesse Ricketson )

Outside the courthouse, Ricketson's son, Jesse, who relocated to Phnom Penh to help coordinate the defence, said he and his family were "utterly devastated" by the ruling.

"It's impossible for me to comment on the proceedings of the court," he said.

"All my thoughts are for my dad and how he must be feeling right now, sitting in a hot prison truck facing what could be the last years of his life in jail.

"The toll on my family is truly brutal."

Sorry, this video has expired Ricketson family 'completely devastated' over six year sentence

The Ricketson family said they would keep fighting despite the ruling.

"The toll of this result, for James, and our whole family and friends is immense. It has, and continues to be a truly brutal experience," the family said in a statement.

"We are in utter shock at this outcome and that James, an innocent Australian, has been sentenced so harshly. Our family lives this tragedy daily."

The family added "James is not a spy" and called on the Australian Government to step in.

"This is a humanitarian issue more than anything else. He could very easily die in there. That would be the ultimate tragedy," they said.

The Cambodian-Australian community called on the Australian Government to condemn Ricketson's conviction and demand his release within four weeks.

"We call on the Government to take action by imposing diplomatic sanction with the recall of Madame Ambassador Angela Corcoran from Cambodia," a statement from the Cambodian Action Group says.

"We urge the Government to retain other diplomatic staff in Cambodia and recall our ambassador."

It also called for "governments of all the free world" to take action against Hun Sen.

"No expression of: 'We urge' or 'We express concern'. Peoples' lives deserve a stronger actions than words or soft diplomacy," the statement says.

Sorry, this video has expired Australian journalist Erin Handley follows the trial of James Ricketson in Cambodia

Prime Minister Scott Morrison told reporters in Indonesia Ricketson would receive consular support.

"He can expect to get all the consular and other support from the Australian Government you would expect in these circumstances," Mr Morrison said after arriving in Jakarta as part of his first trip as PM.

"As usual in these types of events, it is best to deal with these things calmly and directly, and in a way which best assists a citizen."

Minister for Foreign Affairs, Marise Payne, acknowledged Ricketson had been convicted in Cambodia and that a six year custodial sentence had been imposed.

"This is a particularly stressful time for Mr Ricketson and his family, and the Australian Government continues to provide Mr Ricketson full consular assistance," Ms Payne said.

"Mr Ricketson is subject to legal proceedings under Cambodian law and must now consider his response to the court's decision using the avenues open to him under Cambodian law.

"The Australian Government will consider what further appropriate support we can provide after that time."

Emails, photos and letter to Turnbull at core of prosecution

Ricketson repeatedly insisted during the trial that he had no political agenda and his work making documentary films was journalistic in nature.

Character witnesses testified to his filmmaking work and financial generosity to several poor Cambodians.

Following a 14-month investigation, the prosecution produced its evidence: a series of photographs of police in formation or at work, a series of emails between Ricketson and Cambodian opposition leaders, and one letter to then-prime minister Malcolm Turnbull, urging him to rescind an invitation for Hun Sen to visit Australia in 2016.

Sorry, this video has expired Throughout the trial Ricketson has constantly asked who he was supposed to be spying for.

In some emails sighted by the ABC earlier this year, Ricketson told family and friends it was interesting to see behind the scenes of now-exiled opposition figure Sam Rainsy's plans to become prime minister.

In one email from 2013 to a friend, Ricketson made it clear what he thought of the key figures in Cambodian politics, calling Hun Sen "an old fashioned dictator" and referring to him as the villain from Star Wars.

"Prime Minister Hun Sen is the Darth Vader of Cambodian politics … opposition leader Sam Rainsy is Luke Skywalker," Ricketson wrote on August 18, 2013.

In the email, Ricketson cited Amnesty International reports that accused Hun Sen of torturing political opponents.

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The correspondence clearly demonstrates Ricketson's preference for the opposition and poor opinion of Hun Sen, but contains no secret or sensitive information.

The photos, which the prosecution posited were taken by a drone in restricted areas, were clearly taken in public spaces.

Phil Robertson, deputy director of Human Rights Watch's Asia office, said the trial "was an expose of everything that's wrong with the Cambodian judicial system: bogus and unsubstantiated charges, over a year of arbitrary pre-trial detention, prosecutors with little or no evidence, and political hacks serving as judges who rule as ordered rather than based on what happens in court.

"From day one, James Ricketson has been a scapegoat in Hun Sen's charade of 'colour revolution' aimed at toppling the Government.

Ricketson has 30 days to appeal the sentence.

'He could easily die in there'

James Ricketson has been involved in charity work in Cambodia. ( Facebook: James Ricketson )

Having already been locked in the Prey Sar prison for 14 months, Ricketson is suffering a number of health issues including weight loss and constant skin problems.

Ricketson's family says he is being kept in cramped conditions in Prey Sar, suffering because of "lack of sleep, subsistence food and close to zero medical care".

"We would be very concerned about his health over six years in those conditions, and his mental state," Ricketson's nephew Bim Ricketson told reporters in Sydney.

"There are no mattresses and, importantly, very little medical attention available. For someone who is sick and has a number of ailments, it is very challenging for him."

Jesse Ricketson described the filmmaker as an excellent and loving father, uncle, brother and friend to the Cambodian poor.

He also thanked his father's friends and the Australian public for their letters and support throughout the trial.

"The strain on our family and friends and supporters has been immense, but we thank everyone who has supported James and our family through this ordeal," he said in a statement.