Two prison guards have been injured during an attempted escape from Darwin's Don Dale Youth Detention Centre in an incident involving nine people.
The incident has highlighted the need for the ageing centre, which is the site of a former adult prison, to be replaced, while the union representing prison employees said they were understaffed and under-trained.
The group of teenage boys ran away from youth justice workers and climbed on to a roof while being escorted between buildings on Tuesday evening.
Two tried to escape, one by forcing his way through an administration door and another tried to climb a fence and was arrested.
The rest of the teens hit a worker in the face with a fire extinguisher causing bruising and another worker suffered a fractured wrist.
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The youths who tried to escape are likely to be charged.
There was also damage inside a building.
It is the fourth such incident this year in which youths have jumped on to roofs, but there have been no escapes or injuries in 2018 compared to multiple incidents in recent years.
The Don Dale centre was the subject of a report on ABC TV's Four Corners in 2016 depicting the harsh treatment of minors, most notably showing teenager Dylan Voller in a restraining chair wearing a spit-hood, sparking a royal commission.
Minister for Territory Families Dale Wakefield said the incident highlighted how the infrastructure was not "fit for purpose" and that was why the government planned to replace Don Dale as part of the fallout from the royal commission.
However Tuesday's federal budget contained no money to assist the NT government, which has allocated $70 million for two new youth detention centres not due to be finished until at least 2020.
Community and Public Sector Union president Kay Densley said more staff needed to be employed and better training was needed, as residential care workers were being used to plug gaps.
However Territory Families deputy CEO Jeanette Kerr rejected that, saying she was confident about the training given to staff.
"It takes time to develop the workforce," she said.
"When you add a very strong trauma history and complex behaviours you do expect some incidents (in detention centres)."
Opposition leader Gary Higgins said a soft "toning back" approach in the treatment of detainees had gone too far under the Labor government.
