Six inmates at a Sydney jail have been tested for HIV and drug use, after an HIV positive patient was found shooting up drugs and sharing needles with the inmates, sparking concerns about a spread of the infection across the prison.

Intelligence gathered by prison officials led to searches at the minimum security prison last month and the discovery of two inmates in possession of syringes and a third who confessed he had HIV and had been sharing syringes with others.

Sources have told The Sun-Herald that he has also revealed how the drugs were being trafficked into the jail, however no drugs were found during the searches.

It is understood the six prisoners known to have shared the needles have been tested for HIV. Inmates have also undergone urine tests for drugs. The results of the tests are not yet known.

Inmates have expressed concerns that they "have been exposed unwittingly to the virus" and said they discovered what was going on after being were locked in their cells at the Dawn de Loas correction centre.

They have told families and friends that they had their privileges including phone calls and visitors cancelled while officers from the Security Operations Group (SOG) officers scoured cells and common grounds for drugs and implements.

A spokeswoman for Corrective Services NSW said police had been called in to investigate and a " number of inmates have been regressed in classification, moved to other centres, and have had privileges withdrawn as a result."

She said that the area involved was an isolated section of the prison.

Justice Health had also been called in to offer support, testing and counselling for inmates, she added.

A 2009 NSW Inmate Health Survey of 996 prisoners in 30 correctional centres, found 43 per cent had a history of injecting drug use before they were jailed and many claimed they continued to inject while in prison.

Thirty two prisoners said they had started using heroin for the first time while they were in an adult prison and 97 percent of those who injected in prison had shared needles with other inmates.

Professor Basil Donovan from the University of NSW Kirby Institute for Infection and Immunity in Society, said less than one percent of prisoners have HIV compared to Hepatitis C, which is about 35 per cent. He said that injecting in prisons is "typically unsafe" and people can be "remarkably inventive" with many using the same device.

New statistics just released by NSW Health show that there has been one new reported infection of HIV among prisoners almost every year since 2008.

Prisoner advocate Debbie Kilroy from Sisters Inside said that infections like Hepatitis and HIV can spread very quickly because of the high numbers of people doing drugs and sharing needles. "It is a major health concern," she said.

A coronial inquiry last year into the heroin overdose death in jail of inmate Tracy Lee Brannigan, found that the "availability of illicit substances in correctional facilities is an endemic problem".

The spokeswoman for Corrective Services said they had introduced recommendations made by the coroner and expanded its prison contraband search strategy including at or after lock-in time and focussing on inmates who are known or suspected drug users.

She said that Corrective Services conduct "regular, targeted and random visitor and prison searches to detect and seize contraband. CSNSW uses strong intelligence gathering, X-ray machines, metal detectors, CCTV cameras and thermal detection technology to keep contraband out."

In addition to individual prisons carrying out daily cell searches, the SOG which uses sniffer dogs, last year conducted almost 103,000 visitor searches and 86,000 inmate, cell and prison common area searches. These resulted in the seizure of 214 syringes from prisons and 300 syringes from visitors. Out of the cell and prison common area searches 164 inmates were charged internally with correctional offences.

The chair of the Prison Officers Vocational Branch, Steven McMahon, said prison officers are working hard to keep drugs out of jails but need more resources including at least two drug dogs for every centre on every visiting day to keep on top of the problem.

He said that prison officers are serious about finding and removing needles. "We have very tight controls". But he believes the main entry point into the jails remains contact visits between inmates and their families and friends.

The ACT government is considering a needle exchange program for its prison to stop the spread of blood-borne diseases, but Mr McMahon is not in favour of it, he said that needles can be used as weapons and they do not want an increase in the number of weapons among the jail population in NSW which is currently about 11,000.

In jail, the black market price for a syringe is about $200.

They remain the most prized contraband because they are so hard to get and once "owned" can be "rented out" to others.

The most common drugs for injecting remain "the white lady" (heroin) and ice according to Mr McMahon. But research from the NSW Bureau of Crime Statistics and Research is showing a mix of other drugs are now finding their way into prisons including cocaine, cannabis and amphetamines.

Brett Collins from Justice Action said that drugs in jail present very significant health issues for prisoners especially because. "if someone has some gear it is expected they will share".