The benefits expected from an overhaul of the criminal justice system in New South Wales are a "mirage", according to a key section of the state's legal profession.

The NSW Bar Association said the reforms, which are aimed at encouraging offenders to plead guilty to crimes early, will not reduce the enormous backlog in the District Court, which deals with the majority of serious criminal cases.

"It is close to breaking point, the criminal justice system in New South Wales, in particular, in the District Court," Bar Association president Arthur Moses SC told the ABC.

A key element of the reforms is the introduction of a strict set of sentencing discounts which have previously been left for judges to determine.

Those who plead guilty while their case is still in the Local Court will receive a sentence reduction of 25 per cent.

Offenders who wait longer will lose that benefit.

The discount drops to 10 per cent for guilty pleas up to 14 days before a trial and 5 per cent after that.

The Government says this will encourage earlier pleas and reduce time and money wasted on preparing for trials that do not happen.

"I'm hoping we'll see a reduction in the backlog almost straight away," Attorney-General Mark Speakman said.

"…But obviously this will take some time to clear a backlog."

Prosecutors and defence lawyers will be forced to discuss cases sooner, and simpler briefs of evidence will be permitted.

The changes will also see the abolition of committal hearings in the Local Court.

At the moment, magistrates use these hearings to decide whether there is enough evidence for a case to go to trial in the District or Supreme Court.

Sometimes cases do not proceed beyond committal, or only go ahead on different charges.

Under the changes, the role of magistrates in filtering cases will be replaced by a senior prosecutor who will certify charges.

People will still be able to test the strength of evidence by cross-examining witnesses "where appropriate", according to the policy.

Doubts over whether backlog will even be cleared

However lawyers have serious concerns about scrapping the current method of committals.

"It's a judicial officer who's sitting there weighing up that evidence and considering 'is this enough to warrant a matter to go to trial'," Pauline Wright, president of the NSW Law Society, said.

But the Attorney-General said committal hearings had already been removed in England, Wales, New Zealand and several Australian states.

The reforms have the strong support of victims advocate Howard Brown.

Bar Association president Arthur Moses SC wants more Legal Aid funding and more judges. ( Supplied: New Chambers )

"The current system is failing and failing miserably, this new system should make a huge improvement," he said.

But the Bar Association says the changes will not reduce the backlog in the District Court, which is handling more that 2,000 trials and has almost 1,200 sentencing matters pending, on the latest figures.

"I think the Attorney-General is being optimistic in relation to that issue and I don't doubt his bona fides, but I think he's being ill-advised," Mr Moses said.

He said what was needed was a significant increase in Legal Aid funding and more judges on the District Court.

"You can't continue to have a court where there are 2,000 cases pending, with a small number of judges, with increasing workloads," he said.

The Government has allocated $90 million to the package over four years.

"The DPP [Department of Public Prosecutions] and Legal Aid are being consulted extensively about the extra resourcing required and I'm satisfied that that resourcing will be in place," the Attorney-General said.

The changes are expected to take effect on April 30.