A convicted rapist who indecently assaulted a nine-year-old girl and showed a pornographic video to two children has escaped from Darwin's prison after removing his electronic monitoring bracelet.

Northern Territory Police said Eric Ebatarintja absconded from the prison, on Darwin's outskirts, on Sunday evening and are calling for public assistance to help find him.

The ABC understands he was being housed in the worker cottages at the prison complex rather than in the main part of the jail, due to the fact that his sentence had expired, but he was being held under the Serious Sex Offenders Act.

Ebatarintja, 39, who is from Alice Springs, has spent most of his adult life in prison, and had previously escaped the jail with a repeat sex offender and another prisoner in September.

In 2012, Justice Trevor Riley said Ebatarintja had "an unfortunate criminal history" dating back to 1993, and had been imprisoned eight times between the ages of 18 and 33.

His offences included a six-year sentence imposed in 1997 for breaking into a premises and assaulting an 18-year-old woman with a knife, before breaking into the home of an 81-year-old woman the same day and attempting to rape her.

He then violated his parole when he "opportunistically" raped a 50-year-old woman in Alice Springs in 2001 and was sentenced to five years in prison.

In 2012, Ebatarintja pleaded guilty to exposing two girls aged six and nine to a pornographic film showing two people having sexual intercourse, asking the older girl if he could do with her what was being done in the video, and trying to pull down her shorts.

The girls ran away.

Justice Riley said during sentencing for those offences that Ebatarintja's crimes were very serious and sexual in nature, and gave "rise to real concerns as to [his] prospects for rehabilitation".

2017-18 record year for escapes

Ebatarintja was the first person dealt with under the NT's Serious Sex Offenders Act of 2013, and he was imprisoned in 2016 after violating the terms of a series of supervision orders, after having consumed alcohol and cannabis and obtained a phone that he used to view pornography.

"I conclude the risk may be regarded as elevated because the respondent has now demonstrated that he is prepared to breach orders designed to protect the community from any further sexual offending by him," Justice Jenny Blokland ruled in 2016.

"This demonstrates preparedness on the respondent's part to engage in conduct that undermines the protective regime designed to manage the already existing high risk of him committing another serious sex offence."

The court found Ebatarintja had been subjected to sexual abuse by a paedophile male teacher when he was young, and displayed antisocial attitudes and a disregard for the consequences of his actions and for court orders.

It was found that he posed a high risk for general violence, and was deemed unsuitable for supervision within the community by reason of a lack of support; his inability to provide accommodation plans; his history of failing to comply with previous orders, and his continued reoffending.

He was also considered by the court to be at a high risk of repeat offending in relation to both sexual and violent offences, compared to other adult male offenders.

Ebatarintja's escape is the second in one month, after Jasmine Raymond cut off her electronic ankle bracelet while on conditional parole and went on the run for 11 days in May.

She had been sentenced to a nine-year jail term for manslaughter after fatally stabbing her husband outside Darwin's Shenannigans pub in the CBD in 2013.

In 2017-18, 21 people escaped or absconded from Northern Territory Correctional Service's secure facilities, the Attorney-General and Justice Department's annual report revealed, making it a record year since 2014.

Nineteen of those escapees were being held in the lower-security part of the prisons.