The Social Development Minister is defending a youth corrections facility in Christchurch, after figures revealed it had more than 600 security breaches in 10 months.
The figures for the Child, Youth and Family-run facility Te Puna Wai o Tuhinapo show there were 629 incidents in the 10 months to April - including assaults, drug use, and self-harm.
Almost 40 of the 629 incidents were deemed serious or critical, which included assaults against staff, escaping or suicide attempts.
Most of the breaches were classed as moderate, such as verbal threats and wilful damage.
A youth worker, Sione Paea, said the figures were shocking, and more staff were needed in the facilities to prevent such violent incidents.
While Te Puna Wai o Tuhinapo had a ratio of one staff member to every three residents, Mr Paea said if there was a balance there would be more co-operation.
"Security needs to be tightened up, but also the number of social workers needs to be increased in order to balance out with the troubled youth."
Mr Paea said one-on-one support was crucial for getting young people to turn their lives around.
The Social Development Minister, Anne Tolley, says Child, Youth and Family is reviewing the ratio of young people to staff at the facility.
Social Development Minister Anne Tolley said it was important to put the figures into context and understand the difficulties for staff dealing with young people from damaged backgrounds.
She said Child, Youth and Family has assured her a new manager was being installed and the ratio of young people to staff was under review.
Ms Tolley said the wider issue of whether youth justice residences were the right place for young people on remand was also being looked at.
Labour's Justice and Children spokeswoman Jacinda Ardern said some breaches were to be expected in a facility dealing with difficult young people.
But she said a lack of support for staff was driving the numbers up.
"Six hundred dangerous incidents, a number of which were classified as serious, as far as staff being threatened, assaulted, property damage, suicide attempts - these are not incidents at that level that should have been occurring at that frequency."
There was huge staff turnover at the facility, and a heavy reliance on temporary staff, Ms Ardern said.