The number of inmates on remand or serving sentences in prisons in NSW has reached a record level.
The number of inmates in NSW prisons has surged to a record high.
The state's adult prisoner population jumped by 17 per cent in the past two years to more than 12,000, including almost a third on remand having not been convicted.
The Bureau of Crime Statistics and Research, which issued its latest figures on Friday, says the numbers started to rise around November 2014 and are showing no signs of tapering off.
"Normally the number of remand prisoners tapers off from April to August but there was no sign of that last year," BOCSAR director Don Weatherburn said.
"The surge in remand numbers has also been followed by a surge in the number of sentenced prisoners."
Sentenced prisoner numbers rose by nine per cent in the past year, while remand prisoner numbers jumped by 17 per cent.
Dr Weatherburn said the bureau was analysing the cause of the rapid growth in numbers, and expected to report back next month.
Greens Senator David Shoebridge has blamed the surge on a joint Coalition and Labor decision to alter the state's bail laws including removing the presumption of innocence in some cases and expanding the list of automatic bail refusal offences.
"The NSW prison system, and ultimately taxpayers, are now seeing the results of the major parties' failed law-and-order auction with the number of people in jail because they have been refused bail rapidly expanding," he said.
Breakdowns of the figures reveal the number of non-indigenous prisoners has risen faster than the number of indigenous prisoners over the past 12 months.
The number of juvenile prisoners has bucked the trend, falling six per cent last year.
The number of juveniles in custody in December 2015 was 280, compared to a peak of 405 in 2011.
NSW Corrections Minister David Elliott said the government had a strategy in place to meet the needs of a rising prison population, including a new prison in Grafton and expanding Parklea Correctional Centre.
"We have introduced 1985 beds since March 2014, including 430 beds recently introduced to help ease immediate pressure on the system," he said.
"The government is also considering a range of other options."