Renewed calls to address safety concerns at Ashley Youth Detention Centre surfaced again after detainees led a three-hour stand-off on Friday, but the government says work will not be completed until 2021.
Three male detainees caused an expected $20,000 worth of damage to the centre's roof, a camera, solar panels and antennas during the incident.
It was a 2018 election promise of the Hodgman government to upgrade the facilities and tenders for the $7.3 million redevelopment closed on November 20.
A state government spokesperson said they expected construction to redevelop the centre would be completed in 2021.
"A tender process to appoint an appropriately qualified architect is currently underway and a contract is due to be awarded in the new year," they said.
"Planning and design will then take place, and construction is expected to start 2020."
An October report by Custodial Inspector Richard Connock was critical of security measures in place at Ashley, as well as screening processes for visitors, the use of force against detainees and isolation methods.
Parts of the document were redacted but the words were still visible through the black ink.
Labor's Michelle O'Byrne said the stand-off showed the government had failed to respond to the report and address the significant concerns raised about security and safety.
She did not answer whether Labor thought the facility should be shut down or not.
"We've had ongoing concerns about the safety issues at Ashley, for the young people who are interned there but particularly also for the staff who work there," she said.
"We haven't seen the full analysis of the incident yet but it is quite clear that it is not safe for staff there at the moment and the government needs to take action immediately."
Tasmanian Prisoners Legal Service chairperson Greg Barns renewed calls the centre should be closed and not upgraded.
"Stand-offs and violence in youth detention centres only happen because these places are totally inappropriate for young people," he said.
"The government needs to rule out that these young people who may have been involved in these incidents...will not be placed in solitary confinement or isolation.
"Separation means isolation and confinement, it's illegal, it's dangerous and it will simply lead to more violence at Ashley."
He said the centre had a very poor track record in rehabilitation and it was essentially an undergraduate school for Risdon Prison.
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