Asylum seeker processing times have skyrocketed under the coalition government, with people being held in detention facilities for an average of 445 days.
Statistics from the Immigration Department show that of the 1792 people in immigration detention facilities, 23 per cent have been detained for more than two years.
The figures show another 1459 asylum seekers remain in regional processing centres on Nauru and Manus Island, including 68 children on Nauru.
Opposition Leader Bill Shorten said the blowout was unacceptable and called on "gaffe-prone" Immigration Minister Peter Dutton to explain.
"Women and children should not be languishing indefinitely in these facilities," he told reporters in Melbourne.
Opposition immigration spokesman Richard Marles said processing times had more than doubled since Labor was in government, and there was no excuse for it.
"Peter Dutton needs to immediately start taking responsibility for t
he dysfunction he is overseeing."
Comment has been sought from Mr Dutton and the Immigration Department.
Overall, the number of people in immigration detention has fallen sharply since the coalition was elected, following a strong increase between 2009 and 2013 under the previous Labor government.
Of the 1792 people in immigration detention, the bulk are from Iran, followed by New Zealand, Sri Lanka, China, Vietnam and Afghanistan.
Operation Sovereign Borders' monthly update said no illegal maritime arrivals were transferred to Australian immigration authorities or regional processing centres in December.
One illegal maritime arrival volunteered to go home from Nauru, nine were voluntarily removed from Australia while another was involuntarily removed from Australia.
Mr Marles said allowing men, women and children to "languish indefinitely in detention is a disgrace".
At one point during the former Labor government, the average days spent in immigration detention centres was getting near 300.
