Jason Matthew Crutch, 28, committed the latest offences while on parole and after completing a high intensity sexual offenders' treatment program, a Brisbane court has heard.

Crutch was first convicted of sexual offences involving children including possessing child exploitation material in August 2015.

After his arrest on those charges he was released on bail but returned to custody within a month for breaching bail conditions by engaging in inappropriate behaviour with two 15-year-old girls.

Crutch served 11 months behind bars but offended again less than two weeks after his release.

While in the care of his mother on a suspended sentence Crutch had a spate of online contact with girls aged between 13 and 15.

He was sentenced in 2016 for dozens of offences including using the internet to procure children and 27 charges of grooming a child under 16 with the intent to procure engagement in a sexual act.

In February the following year Crutch digitally raped an intoxicated 17-year-old after walking her home.

He was also convicted in 2020 of contravening a supervision order by connecting to the internet and operating social media accounts to which Crutch added children.

Crutch pleaded guilty in Brisbane District Court on Tuesday to offending again while on parole and "very much in the same style" as offences committed earlier, Judge Michael Byrne said.

A phone found in his possession by corrective services officers contained 121 images and 34 videos of child exploitation material depicting children aged from four years old.

Crutch had also been communicating with a 15-year-old girl whose contact details he stored under the name "My Wife".

Initially claiming to be aged 18, Crutch requested photos of her and sent images of his penis and videos of himself masturbating.

She immediately stopped communicating when Crutch admitted being 26 and in prison for sexual offences.

Crutch pleaded guilty to seven counts of indecent treatment of a child, and one count each of possessing child exploitation material and using an electronic communication to procure a child.

Judge Byrne said the plea reflected a willingness to facilitate the administration of justice.

But with Crutch's "terrible history" the judge could not regard the plea as showing remorse.

Crutch was diagnosed at a young age with Attention Deficit Hyperactivity Disorder and Asperger's Disorder, struggled at school and socially and was horrendously bullied, his barrister James Benjamin told the court.

Judge Byrne said there is no doubt Asperger's had some role in Crutch's offending.

"You are unable to control that to some degree, but I emphasise, to some degree," he told Crutch.

But he said many people with a spectrum disorder are able to learn to control certain activities.

"The simple reality, Mr Crutch, is that, if you do not do something about this re-offending you will spend the whole of your life in jail," Judge Byrne added.

Crutch was sentenced to three years and six months behind bars.

With time already served, he will eligible for parole in May.

Australian Associated Press