The NSW corrections minister is "appalled" after it was revealed a female prison guard had a sexual relationship with an inmate.
Allegations of prison guards sleeping with inmates in NSW jails will be investigated by a special task force.
Minister for Corrections David Elliott announced on Wednesday he'd instructed the state's jails commissioner, Peter Severin, to establish a task force to investigate the claims.
The investigation would be led by an independent person and examine alleged misconduct dating back 10 years, Mr Elliott told AAP in a statement.
"I have also instructed the Department of Justice secretary to provide options for an increase to the penalties for misconduct," Mr Elliot said.
"This will include sexual an inappropriate relationships between inmates and correctional staff."
Mr Elliott said he was "appalled" by the revelation a female prison guard at a NSW mid north coast jail was suspended amid claims she'd had a sexual relationship with a convicted cop-killer.
"I am keen to see what options we could implement to ensure this is never allowed to happen again," the minister said.
The guard was reportedly involved with Sione Penisini who is serving a 36-year sentence for the murder of Sydney police officer Glenn McEnallay in 2002.
Mr Elliott has also apologised to Sen Const McEnallay's mother who was angered by the allegations.
It is not a criminal offence for an officer to be in an inappropriate relationship with an inmate but it is a breach of the Corrective Services NSW code of conduct, a spokesperson told AAP.
"CSNSW does not tolerate this sort of behaviour and there have been only a very small number of staff who have engaged in this conduct," the spokesperson said.
Prison staff must pass several screenings including criminal record checks before being employed and, once hired, must maintain personal and professional boundaries, the spokesperson added.
Sen Const McEnallay was shot four times in the chest and head after pursuing a stolen car at Hillsdale in March 2002. He died of his wounds in hospital a week later.
Four men were jailed over the killing including Penisini who admitted pulling the trigger.
Penisini has been transferred to another prison in the wake of the scandal.