Australia got enmeshed in a nasty human rights violation scenario as 23 Indonesian minors prepare to file a civil suit against the federal government on allegations they were locked up in adult prisons where they suffered abuse.

The teenagers were part of the 50 ''people smugglers'' that were jailed in Australia between 2008 and 2011. They have since been returned to Indonesia.

Lisa Hiariej, a lawyer for the plaintiffs, said the 23 former detainees demand a public apology from the Australian government as well as compensation for damages incurred while being held up in adult prisons despite being minors at the time of the offense.

"We demand the Australian government apologise and give them compensation," she said.

"We haven't decided how much we're demanding because we have to calculate first how long those kids were detained for and so on."

Reports said the kids were jailed for an average of more six months. They were later released without convictions.

Ms Hiariej said two of the boys, aged between 15 and 16 years that time, have been traumatized because of the sexual harassment they experienced from the older inmates.

''They were not touched at all but the adult prisoners showed them their genitals and showed them how to have sex."

''They are now traumatised by it, the memory of being sexually harassed keeps coming back..."

The teenagers were jailed following routine procedure of wrist X-ray tests, which said they were over 18 years old, an actually outdated and unreliable method criticised by experts.

If solely based on wrist X-ray tests, the boys would really appear older because laborious work as fishermen everyday of their lives had made their wrists "more developed," according to Apong Herlina, Indonesia's National Commission for Child Protection deputy chief.

"The X-ray technique fails to factor in the child's nutritional conditions and race. Therefore, the technique should not be used to assess people's age," Apong said.

The 50 boys were part of the 180 Indonesian boat crew that the Australian Human Rights Commission reported in 2012 that were held in custody or jailed despite underage claims.

A spokesperson from the Australian Attorney-General's Department said the government had not yet received any formal notification of the claim.

"The government has not received any formal notification of this claim. Where it is considered that such claims do not have merit, the Australian government will defend them," the spokesman was quoted by The Australian.