Health and social workers who've worked in Australia's immigration detention centres have rallied against a new law which could see whistleblowers jailed.
The Australian Border Force Act comes into force today and provides for up to two years in jail if centre workers disclose information about the facilities.
Doctors and social workers have already spoken out about the poor conditions at centres on Nauru and Manus Island.
A doctor who used to work at the Christmas Island centre John-Paul Sanggaran is circulating an open letter to Australia's Prime Minister and Opposition leader against the law.
He says a wide range of former workers have signed it, including doctors, nurses, psychiatrists and humanitarian workers.
"I think it just adds to the message that this is varied people in lots of different places that are seeing things that are just unacceptable and this idea of giving us two years' jail if we decide to stand up and do something about it is just completely unacceptable."
Dr Sanggaran says the law will have a chilling effect, and people will be even less likely to speak out.