Locking up at Maghaberry prison
The prisoner ombudsman has been accused of calling into question the integrity of the police.
If follows Pauline McCabe's call for an investigation into claims of excessive force by some members of specialist search teams at Maghaberry prison.
Fifty complaints have been made in the last two years, but no-one charged. Mrs McCabe wants the cases reviewed.
Finlay Spratt, of the Prison Officers Association, said the complaints had been properly investigated by the PSNI.
"Prison officers are reported on a regular basis to the police for alleged assaults. That's investigated by the PSNI who are the body that should investigate those complaints," Mr Spratt said.
"We have many procedures, we have the independent monitoring board who are in Maghaberry more often than the prisoner ombudswoman is and I've received no complaints."
Mr Spratt said five members of the Maghaberry standby search team had received death threats from prisoners and said the ombudsman did not understand prison culture.
"If you're disrupting drug trafficking, they're (prisoners) obviously going to complain and they're going to try every method they can to discredit those individuals who are doing their jobs," he said.
Mrs McCabe has written to Security Minister Paul Goggins calling for police investigations to be independently reviewed.
"Twenty-three of the Maghaberry cases have been referred to the PSNI in 2008/09, 18 of them since October 17 2008," said Ms McCabe's letter to the security minister.
"To date the Public Prosecution Service has considered eight of those cases and, in line with the above, made a decision of no prosecution in all cases.
"I believe that this is because the standard of evidence required to support a prosecution is not available where a case typically involves the word of one prisoner against three, four or even five officers."
The Ombudsman said further allegations of misconduct had been made privately by prison staff concerned at the conduct of colleagues, but she claimed none of these allegations had been officially lodged.
In a statement the Prison Service said it had already started a a review of the SST's role at Maghaberry in order to ensure that its work is carried out effectively.
It added: "The primary role of the standby search team is to search for contraband and illicit materials, particularly drugs.
"There have unfortunately been drug-related deaths in prison and were it not for the efforts and vigilance of the SST there would have been potential for further loss of life.
"Because of the role they perform it is not surprising that prisoners may make complaints against SST team members."