NSW juvenile prison numbers on the rise

Children and teenagers in NSW have been increasingly refused bail in what the NSW Law Society says is a disturbing trend.

The state prison population is rising, and the percentage of juveniles in custody increased by 16.3 per cent to 293 in the last quarter of 2014.

The increase has been attributed to a 52.1 per cent growth in the number of prisoners aged 10 to 17 who have been refused bail, according to data from the NSW Bureau of Crime Statistics and Research.

NSW Law Society president John Eades says the figures are disturbing.

"Because if you allow these young people to go into custody, there is a greater risk of them learning inappropriate activities," he told AAP.

"They are mixing with other people who are in there for serious criminal offences."

In the past five years, 83 per cent of juveniles in remand have not received a custodial sentence.

The law society has urged the state government and opposition to commit to reform.

"(They should) ameliorate these disturbing statistics for juveniles," Mr Eades said.

For adult defendants, the figures also show a surge in those behind bars who are awaiting trial or sentencing.

In the second half of 2014, the adult prison population rose by 2.4 per cent, with 3015 people waiting for their case to proceed while on remand.

Those refused bail were most likely to be facing charges involving acts intended to cause injury, drug offences and robbery or extortion.

Although he also found those figures disturbing, Mr Eades said the reason behind them was not clear.

"The fluctuations would have to be examined in detail," he said.