The advocate's office has no power to investigate and cannot compel information from mental health facilities or the youth criminal justice system after children make complaints, said Elman.
As an example, Elman talked about a young girl who called his office to report she'd been sexually assaulted by a staff member at a mental health unit. He looked into it, only to be told he couldn't access the investigator's report into her case.
"She had the courage to phone us, the courage to ask for help, and we say: 'We're doing our best but I'm sorry, they say they did an investigation and everything's fine, but we can't see it,'" said Elman.
"How does that make sense to that 12-year-old child?"
The advocate's office has been raising concerns for five years about the government's refusal to provide copies of investigation reports into allegations by young people in youth justice facilities who say they were assaulted by staff.
"The reason we keep asking for those reports is because we are concerned that the allegations are not being properly investigated," said Elman.
When the advocate's office does get copies of investigation reports, it finds the investigators often relied on the written reports of the staff who were involved, "and then determined that the allegations are unfounded," added Elman.
The advocate said the Ministry of Children and Youth Services told him the request to increase his power to compel information "would create too much document process" for service providers.
"I was told that we probably should be spending money on service and not on a robust system of oversight," said Elman.
"How is it a burden to provide me with documents that already exist, or should exist? How is allowing me access to information costing money?"
The New Democrats rejected the government's arguments that giving the children and youth advocate powers to compel information would mean too much time would be spent producing documents.
"It is unacceptable that the Ministry of Children and Youth Services is using paperwork as an excuse to deny Mr. Elman investigatory powers over his full mandate," said NDP critic Catherine Fife.
The Progressive Conservatives said it's clear Premier Kathleen Wynne's talk about running an open and transparent government doesn't extend to the Ministry of Children and Youth.
"It is imperative that the advocate is given the necessary powers to inquire, investigate, interview witnesses and produce high-impact reports," said PC critic Jim McDonell.
The government said it had agreed to give the advocate the authority to investigate the child welfare system, and would look at giving Elman oversight of the youth mental health system once a review is completed.
"Once the transformation of the children and youth mental health system is complete, expanding (the advocate's) powers to this sector is something we would consider," Children and Youth Minister Tracy MacCharles said in a statement.
Elman said MacCharles' comments were a strange admission from the government.
"I'm actually surprised that they took that stance and took it public because I think it's ludicrous that the children's mental health system is too fragile to allow children to speak up," said Elman. "How does that make sense to the children?"
MacCharles issued a second statement later Friday rejecting Elman's request to be able to investigate complaints from youth in the criminal justice system.
"The purpose of (the office) is to advocate on behalf of children, not to investigate criminal matters," he said. "Currently, the police are best positioned to conduct to these types of investigations."
Elman also wants whistleblower protection for service providers who report incidents involving children to the advocate's office because the current law only covers the civil service, not employees who work in agencies funded by the province.
He also criticized the Liberals for limiting his responsibilities to investigate complaints from children who say they were assaulted at provincial schools for kids who are deaf, blind, deaf-blind and severely learning disabled.
"The young people have brought concerns forward, and we would like to do a review and speak to all the students," said Elman. "They said we only had the right to do 'informal advocacy' in those schools, and we did not have a right to access that information."
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