Phnom Penh: Jailed Australian filmmaker James Ricketson has sent a letter to Cambodian Prime Minister Hun Sen apologising for "any disrespectful comments"he had made regarding his leadership and his government.

The letter was published by The Khmer Times, which said it was forwarded to them by Ricketson's son Jesse.

James Ricketson, who is accused of espionage, exits the prison van as he arrives at the Phnom Penh Municipal Court for a court appearance. Credit:Kate Geraghty

"I now realise that my statements I have made in the press and other media are disruptive and ill-informed. These statements were made from a place of foreign naivety and ignorance about the complexities and difficulties of governing Cambodia," Ricketson wrote.

"I sincerely regret having made any disrespectful comments and I unreservedly apologise in this regards to yourself and your government."