Ricketson's family 'devastated' by ruling

Australian filmmaker James Ricketson has been convicted of espionage and sentenced to six years in a Cambodian prison, leaving his family "devastated" and concerned about his welfare.

The 69-year-old was on Friday sentenced by three judges in Phnom Penh, 15 months after being detained after flying a drone without a permit over a political rally.

Nephew Bim Ricketson said the family was hoping for the best but have been left devastated by the verdict and lengthy jail term.

He was hopeful his uncle would be found innocent, adamant he was not involved in espionage.

They are extremely concerned about his welfare, noting he has lost a lot of weight, has skin problems and many undiagnosed health issues.

The legal battle has been a heavy strain on the family, with son Jesse Ricketson and his partner Alexandra relocating to Cambodia.

The defence has a 30-day window to appeal or accept the verdict and seek a royal pardon.

The family is seeking support from the Australian government to put pressure on Cambodia to release James Ricketson.

Prime Minister Scott Morrison promised the Australian government would keep providing consular support.