Questions have again been raised about security at Tasmania's Risdon Prison with revelations police are investigating allegations a Justice Department employee had a sexual relationship with a violent inmate.

They are also investigating whether the woman smuggled in contraband goods to the prison for Rodney Gene Crosswell.

Crosswell still has five and a half years to serve for firing a sawn-off shot gun at Constable Holly Dillon in 2010.

On the same day, Crosswell held up a Claremont newsagency, put a gun to a woman's back and threatened to shoot her, and stole and torched a car.

The last time he appeared in court, Crosswell was flanked by six prison guards and observers were told to sit at the back of the room in case he became violent.

He has also served time in Victoria for manslaughter.

Now it has been revealed police are investigating allegations Crosswell and a woman who works for the Justice Department had sex with the violent criminal inside the prison on a number of occasions over a six month period earlier this year.

They are also looking at allegations she smuggled into the jail a range of contraband goods, including a mobile phone, for Crosswell.

Tasmania Police has issued a statement confirming it is investigating a "matter referred by the Justice Department and that no charges have been laid at this time."

The statement also makes reference to suggestions the same woman could have accessed the firearm's database for Crosswell.

"Tasmania Police can categorically state that the firearms database has not been breached and has ruled out that any suggestion that persons being investigated in this matter have accessed the firearm database."

It is understood the woman also sought information on the prison's tactical response group

The Justice Department is not commenting saying it is a matter for police.

The Corrections Minister, Nick McKim, also declined to comment.