A group of 40 teachers, doctors and social workers who have worked at detention centres on Nauru and Manus Island have dared the immigration department to prosecute them.

The Border Force law came into effect on Wednesday and includes a two year jail term for detention centre staff who blow the whistle on abuses and disclose confidential information.

In an open letter to Prime Minister Tony Abbott and Immigration Minister Peter Dutton, the group has vowed to continue to advocate for those to whom they have a duty of care despite threats of imprisonment.

"Because standing by and watching sub-standard and harmful care, child abuse and gross violations of human rights is not ethically justifiable," they said. 

The AEU NSW Teachers Federation branch, a union that represents 33,000 teachers in New South Wales and the ACT, has come out strongly in opposition to the Abbott Government's move, saying this decision impinges on civil liberties and human rights and indeed, the rule of law itself.

General Secretary of the Independent Education Union, John Quessy said: "From today, teachers face two years gaol if they as much as express concern or speak up about students they are teaching in detention centres. The sinister Border Force Act Section 42 makes it an offence for an "entrusted person" to "make a record of, or disclose" protected information, an offence which is punishable by up to two years in gaol." 

There is a legal requirement in NSW under the Ombudsman Act 1974 and the Children and Young Persons (Care and Protection) Act 1998 for teachers to report suspected risks to children in certain circumstances, and they may face penalties for non compliance.

"Has the government learned nothing from the Royal Commission into Institutional Child Sexual Abuse? Would the Prime Minister be happy to accept that those caring for his children were fearful of speaking out about suspected abuse? A consequence of these laws, perhaps unintended, is that abusers will be protected and not exposed," Quessy said.

"The Abbott Government's laws and policies foster a climate of fear and intolerance, threaten democratic processes and basic human rights," he added. 

Dutton also released a statement, claiming reports in the media that the Australian Border Force Act will inhibit people from speaking out about conditions in immigration detention or immigration processing centres are incorrect.

"The ABF Act ensures that secrecy provisions in the department are in line with partner and like agencies, such as the Australian Federal Police and the Australian Defence Force," he said.

"Under existing laws, such as section 70 of the Crimes Act, there is already an offence provision with the same penalty that extends to the unauthorised disclosure of information by a Commonwealth officer, the definition of which extends to those performing services of behalf of the Commonwealth.

"To be clear, I am aware of claims by certain groups and industry bodies that the Government is aiming to prevent people with legitimate concerns from speaking out about conditions in immigration facilities.

"These claims are not accurate," he said.

Apologies to Bill Shorten, it's not his legislation but I thought it was a funny meme