A registered child sex offender was able to visit and consort with five paedophiles in a WA jail 20 times before being arrested over fresh crimes, including conspiracy to rape a five-year-old girl.
The man made visits while on parole for child sex crimes in a case that highlights an apparent loophole the State Opposition says puts children at risk.
The Opposition said urgent action was needed to ensure police were alerted immediately when registered child predators tried to network with other paedophiles behind bars.
In the District Court last week, the 33-year-old was given more than eight years jail for 14 fresh child sex offences involving two children. It emerged he was being "hassled" by another paedophile for photos of the five-year-old and had planned to pass them on.
Police can issue orders to ban registered child sex offenders consorting with another paedophile but must first become aware of the contact.
It is also only after the order is issued that police can prosecute them for "habitually" consorting with fellow child sex predators.
The court was told that at the time of the paedophile's arrest in 2012, police had complied but not served non-contact orders.
The prison visits were over five months and were to five child predators at Karnet Prison Farm, where the man also served time for child sex crimes.
Some visits were while he was still on parole.
A police spokeswoman said WA prisons knew the names of all convicted paedophiles jailed in WA but were under no "obligation" to report such visits to the WA Police sex offender management squad that monitored registered paedophiles.
She said a process to formalise sharing such information was still being finalised.
A Department of Corrective Services spokeswoman said convictions did not automatically preclude a person from visiting jails and the criminal history of each visitor was not investigated.
An alert was put on a prisoner's file banning contact with certain visitors after the department became aware of a prohibition.
Police could also access DCS records of visits to prisoners.
It is understood there is no automatic system to alert police immediately a registered sex offender visits a paedophile in jail.
Instead, DCS and police carry out intelligence operations to foil such networking.
Shadow corrective services minister Paul Papalia said the lack of an automatic alert was a failure that endangered children.
Corrective Services Minister Joe Francis' office did not respond yesterday.