The Queensland government has banned jailed sex offenders from being released to perform community service work, after reports of projects being run near schools.

Corrective Services Minister Judy Spence ordered an urgent internal investigation into claims that four sex offenders from Palen Creek Correctional Centre, about 100km south of Brisbane, have been released to work on community service projects near schools on at least seven occasions.

She has also sought a probe into alleged security lapses during NAIDOC (National Aborigines and Islanders' Day Observance Committee) Day celebrations at the low-security jail near the small community of Rathdowney.

The second investigation followed media reports that a child-sex offender was allowed into a change room where children were dressing for a dance performance.

"My position is very simple - that it's unacceptable for there to be any risk from sex offenders to the community and we will make whatever changes are necessary to ensure people follow the directive that has been issued," Mr Beattie said.

"The reality is that recent evidence suggests that many paedophiles, for various reasons, have got to a position where they are basically incurable," he said.

"This is a fairly consistent pattern and what's happening is there isn't any real concerted response to the danger that these offenders pose to the community," she said.

Ms Johnston said all sex offenders should be detained until they could prove they were rehabilitated and should face regular testing after they were released.

Civil liberties lawyer Terry O'Gorman said the situation at Palen Creek was not out of the ordinary and Mr Beattie should not make policy on the run.

"The very strict corrective services classification system means a battery of tests are applied before a person is given a low security rating," Mr O'Gorman said.

"It would be disappointing if meaningful rehabilitation programs were changed on the basis of a sensationalist story that is low on factual justification.

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