One-in-three people behind bars in NSW is now on remand and not convicted of a crime, a growth of more than 10 percentage points in five years.

The news on re-offending, released on Friday, also makes for difficult reading for the state government: it has gone up for every year the law-and-order focused coalition has been in power in NSW.

But in an interview, the Corrections Minister, David Elliott, who presides over the most crowded prison system in NSW's chequered correctional history, has outlined a plan to drop that figure.

In a transparency overhaul that echoes federal and state pushes to improve schools and hospitals, Mr Elliott will be introducing performance measures for all NSW prisons. Each will be judged on criteria such as how often inmates reoffend, inmates' quality of life behind bars and the time inmates spend outside their cells.

"My motivation is to increase standards and reduce re-offending," Mr Elliott said. "You have to link those."

NSW's re-offending rate is the worst of any state. It rose this year to 48 per cent this past financial year, up nearly one percentage point for every financial year since the government took office in 2011. Only the NT has a worse record.

Premier Mike Baird has staked his government's reputation on making that figure go the other way: achieving a five per cent drop by 2019 is one of his government's stated priorities.

Mr Elliott says he thinks greater transparency can help achieve that and has committed to publishing the figures.

"I don't want to be the Minister for prisons known for opening new cells," he said.

The move follows a damning report last year of the state's overcrowded prison system, where three men share a cell and more than 50 a phone – a febrile atmosphere that leads to fights, listlessness and little exercise or time outside of cells.

UNSW Criminologist Eileen Baldry says the blame – and fix - for overcrowding and recidivism lies with another branch of the government: the courts.

The state government overturned a liberalisation of the state's bail laws more than one year ago, a move Dr Baldry says was driven by rare instances of violent acts performed by prisoners on bail.

She says the tougher laws lead to many people being returned to prison and placed on remand for non-violent breaches of bail conditions such as drug possession.

"They are immediately counted as recidivists," Dr Baldry said.

In  1970, only one in 10 prisoners was on remand.

The Australian Lawyers' Association says a lack of accommodation and mental health services means prisoners who would otherwise be granted bail end up on remand for a lack of alternatives.

The pressure has only increased with new statistics showing the prison population rose 12 per cent in 2015 to hit a record of 12,100 inmates.

Mr Elliott says the government is spending $1.3 billion a year on the portfolio and has recently put 430 beds into the system.

Analysis by the NSW Judicial Commission and the Jesuit Social Services has suggested about 40 per cent on remand will receive no additional time because they receive a non-custodial sentence.

Up to 10 per cent of remandees are found not guilty.

The statistics did bring some good news: rates of juvenile incarceration have fallen by 6 per cent.

The cost of maintaining this growing segment of the prison population is likely close to $300 million.

It costs the state in excess of $70,000 a year to keep each of its prisoners on remand.

A spokeswoman for the Attorney-General, Gabrielle Upton, said changes to bail laws were made to make the community safer but would be monitored.

In a report last year, BOCSAR attributed the rise in people on remand to people breaching bail conditions, not changes to legislation. The overall rate at which bail is refused by courts had held steady, the report found.