The 68-year-old has been detained since June when he was arrested and charged with espionage after flying a drone over a political rally in Cambodia's capital.
For several years, he has provided humanitarian support to Cheung Ek, a poor community in the country's capital, and residents said they were devastated by his detention.
One resident, sorting through a pile of rubbish on the dusty outskirts of Phnom Penh, said life was hard but Mr Ricketson made it a little easier — with support even continuing from his prison cell.
"He helped the elderly, the sick and the babies that needed formula," Lim Nak said.
"He doesn't discriminate against the poor as long as they asked him for help.
"After giving birth, he still sent this lady money even though he's in prison. This is his heart for the Cambodian people."
Another Cheung Ek resident, Leng Kak, said Mr Ricketson's arrest had devastated the community.
"We feel pity for him because when he came here he never did anything wrong and he helped us. We are poor," he said.
'I want to appeal to Australians'
Mr Ricketson has been charged with espionage, accused of collecting material prejudicial to Cambodia's national defence with the intent to supply it to a foreign state.
His arrest came amid a crackdown on the opposition, and freedom for media and civil society, by the government of Prime Minister Hun Sen.
Despite his humanitarian work, Mr Ricketson is a controversial figure.
While he has his supporters in Cheung Ek and the other poor Cambodian communities he has helped, he has his critics too.
Twice convicted of defamation, he has been involved in long-running feuds with several organisations and individuals in Cambodia and in Australia.
But Leng Kak said Mr Ricketson was no spy and his only mistake was to fly a drone without a permit.
"He's not a spy. He came to help Cambodia. He's not a spy. He made a small mistake that he did not know about," she said.
"I want to appeal to Australians to have him released quickly. It is a pity for him."
Mr Ricketson has appealed to Cambodia's Supreme Court to be released on bail while the investigation into the spying charge continues.
It is expected to hand down its decision next week. If he eventually faces trial and is found guilty the maximum penalty is 10 years in jail.