A leading criminologist has warned overcrowding at the ACT's only jail may jeopardise safety and security, while urging against ''disgraceful'' proposals to send prisoners interstate.
The Alexander Maconochie Centre is now facing serious overcrowding issues, with inmate numbers rising by 40 per cent since January, culminating in a record high of 340 on Sunday.
Canberra criminologist David Biles believes the jail - which was recently expanded from 332 to 366 beds to cope with surging prisoner numbers - is currently stretched beyond its operational capacity.
Mr Biles said the jail would need roughly 400 beds to safely juggle the number and categories of inmates now behind its walls.
He fears the ''startling'' volume of detainees could lead to security and safety issues within the AMC.
Those concerns came as Opposition Leader Jeremy Hanson on Wednesday accused the government of covering up a report compiled by John Walker in 2001, which suggested the ACT's jail would be full almost immediately.
Mr Hanson said the AMC's opening capacity of 300 beds, reduced from 374 because of budget pressures, was ''never going to be enough''.
''Simon Corbell assured the Assembly that the jail would have capacity for 25 years, but he did so knowing they had plenty of advice saying it would be full the day it opened,'' he told ABC Radio.
''They've consistently lied about the capacity, they've covered up reports and advice.''
The government is now taking urgent steps to try to deal with pressures at the jail.
They have added more bunk beds to cells and cottages to increase its capacity to 366 beds, while installing separation barriers in accommodation areas to prevent contact between certain types of prisoners.
The government is also considering sending a handful of prisoners interstate, if it is decided there are better support programs for them outside of the ACT. But Mr Biles said other options should be considered before moving prisoners away from their home state.
He believes authorities should consider transferring female inmates somewhere else to free up space, or turn the weekend detention centre into a full-time correctional facility.
Corrections Minister Shane Rattenbury said authorities were only considering sending a small number of prisoners interstate.
He said they would consider whether it could better use the Periodic Detention Centre, but said moving women out of the AMC would be a ''major exercise'' with high costs.
Attorney-General Simon Corbell, who was Corrections Minister when the AMC opened, has refused to answer questions on the Walker report, or comments he made in 2011 about how the government decided on the facility's capacity.
with Lisa Cox