Darlene MacDonald said she has received calls from judges who want to release youths from police custody, but can't because the young people don't have anywhere to go.
Judges have said they don't want to see youth put up in hotels, so the children remain in jail until Child and Family Services can find somewhere for them to stay, she said.
"It's a lack of foster placements," MacDonald said in an interview with The Canadian Press. "It's a lack of any placements that could give stability to the child."
MacDonald said she recently visited Manitoba's youth detention centre and was distressed by the stories of children there. Suicide is not uncommon for kids who have been incarcerated, she said.
"Just the feeling of hopelessness and depression, particularly if they don't have any family members visiting them or any hope in their life, any hope for the future," MacDonald said. "Think of the extreme circumstances they've had in their life and then to be incarcerated with no therapy or wrap-around services — that's very, very concerning."
Family Services Minister Kerri Irvin-Ross declined to be interviewed. Her spokesperson, Rachel Morgan, said in an emailed statement that children in custody have "complex needs and require appropriate placements to meet those needs.
"They can't be placed in the community without those services in place."
The province is working on increasing the number of foster spots, she added.
Manitoba has more than 10,000 children in care. The vast majority are aboriginal. Over the last decade, the Child and Family Services Department has been harshly criticized for housing children in hotels because of a shortage of foster homes.
Cora Morgan, executive director of the restorative justice organization Onashowewin Inc., said kids in care are often charged by group homes for actions such as punching a wall or throwing an empty water bottle. Once a child is in custody, she said, Child and Family Services doesn't move quickly to find another placement.
In one case, Morgan said, a group home dropped charges against a girl in their care, but she languished in detention because she had nowhere else to go.
"She had no charges pending, but she stayed there for weeks."
Most provinces automatically divert charges laid by group homes so that the matter is resolved without jail time, Morgan said. Manitoba does not and once children are taken into custody, they become much more costly and difficult to get back on track, she said.
"If you don't attend court monthly, there is a warrant for your arrest."
Grand Chief Derek Nepinak with the Assembly of Manitoba Chiefs said he has raised the issue with the attorney general and the family services minister, but nothing is being done. Vulnerable kids are caught up in the justice system unnecessarily rather than being in a loving, nurturing home, he said.
"We're jailing our own children. It's one of the worst atrocities that we can imagine."
Corey Shefman, president of the Manitoba Association of Rights and Liberties, said keeping kids in custody is a violation of their right to due process, as well as of their right not to be arbitrarily detained.
"It's even worse than arbitrary detention. It's detention of convenience, the convenience of government actors," he said. "The government is dropping the ball."