TORONTO -- Ontario's children's advocate is calling for the government to end the practice of placing youth in solitary confinement for more than 24 hours.

The Provincial Advocate for Children and Youth reviewed the province's 20 youth justice facilities and found that many youth have been subject to what it calls dehumanizing conditions while in solitary confinement.

Irwin Elman, provincial advocate for children and youth, said that while solitary confinement for youth is permitted under Ontario law, an absolute ban on placements that exceed 24 hours would be consistent with the United Nations' position.

"Youth justice custody is supposed to give young people the opportunities for rehabilitation so they can turn their lives around and later reintegrate into society," Elman said Wednesday in a statement. "Solitary confinement runs counter to this model since it negatively harms an individual's mental and physical health, especially those with a mental health issue."

Youth interviewed for the report described their experiences as "inhumane," often suffering extreme heat or cold, little access to fresh air, no bedding during the day or prolonged periods without toilet paper or flushed toilets.

Half of the 141 youth interviewed said they were denied access to a lawyer, and some said staff taunted them and called them "sissies" when they asked to contact the advocate's office.

The report found that the youth justice facilities have been increasingly placing youth under 16 in solitary confinement -- there were 186 placements last year, up from 106 in 2013.

It says youth have been placed in solitary confinement for periods between one minute and 15 days, and 38 youths received more than 72 hours in solitary confinement in 2014. According to Ontario's Child and Family Services Act, children under 16 cannot be held in solitary confinement for more than eight hours per day or 24 hours per week, and those 16 and over cannot be held for more than 72 hours without approval by a provincial director.

However, the report found an overall decrease in the use of solitary confinement across the youth justice facilities, with a total of 701 placements in 2014, down from 1,021 in 2009.

Tracy MacCharles, children and youth services minister, said her ministry will thoroughly review the report's findings and noted that solitary confinement placements in Ontario youth justice facilities are on a downward trend. She said the current use of solitary confinement is lawful, and used only to ensure physical safety, not as punishment.

"Our approach is working: the youth crime rate in Ontario is now 46 per cent lower than it was in 2003 and the youth justice admission rate has fallen by 72 per cent," she said.

"While we have come a long way in developing a service system that meets the unique needs of youth, we know there is more that can be done and we will continue to work with the advocate."

Premier Kathleen Wynne said Wednesday that she had not yet seen the report, but the problems it highlighted were concerning.

"The advocate has done his job and has shone a light on some issues that of course we're concerned about, and that we will need to work with him to rectify. Absolutely," she said.