Hundreds of children in Iraq have been charged with links to terrorism, many of them based on confessions obtained through torture, a human rights group has found.

Iraqi and Kurdish authorities are detaining approximately 1,500 children, 158 of whom have been charged with alleged affiliation to Islamic State of Iraq and the Levant (Isil), according to a new report by Human Rights Watch.

The report claims the prosecutions are often based on dubious accusations and forced admissions.

The 52-page report, entitled "Everyone Must Confess': Abuses against Children Suspected of ISIS Affiliation in Iraq," criticised what it described as a deeply flawed screening process that often leads to detention and prosecution of children regardless of whether they have any involvement with Isil, or the extent of that involvement.