Every year, Victorian taxpayers save $3.8 million on prison beds, on which drug offenders would otherwise rest their heads, but for Dandenong's Drug Court. The social and health savings, Drug Court Magistrate Tony Parsons says, cannot be quantified.

On Saturday, the state government will announce a massive expansion to the Drug Court's operations, which is expected to almost triple the number of offenders given the chance to turn their lives around.

Attorney-General Martin Pakula said the state government had set aside $32 million in the 2016-17 state budget to massively expand the Drug Court's operations into the Melbourne Magistrates' Court.

This will mean that drug abusers facing jail for serious drug-related crimes in a wide catchment, area including Footscray to the west, Northcote and beyond in the north, St Kilda to the east and Brunswick and Coburg in the north-west, can qualify to have their cases heard there. Previously, only those living near Dandenong qualified.

"The lack of effective sentencing options for serious drug-related offences has resulted in increased imprisonment rates, increased re-offending and a failure to address the underlying causes of addiction," Mr Pakula said.

"The Andrews Labor government is committed to providing a more effective and alternative approach and the Drug Court model offers offenders a real opportunity to turn their lives around."

The court gets results: people who go before the Dandenong-based division of the Magistrates' Court are 30 per cent less likely to reoffend than others charged with drug-related crimes and sentenced to traditional punishments.

It's expected the funding will increase the number of people who can appear before the court from about 70 a year to about 240.

At Drug Court, offenders are sentenced to a two-year custodial sentence served in the community while they undergo a drug treatment order.

Typically, that includes conditions such as regular drug testing, working with a case manager, drug and alcohol counselling and regular appearances before the magistrate, who assumes some responsibility for guiding offenders through the process.

In 2014, audit firm KPMG conducted an independent assessment of the court, finding that 83 per cent of people who completed a drug treatment order through the court between 2006 and 2012 did not reoffend while on their order.

After 12 months, people who took part in the program showed a 23 per cent drop in recidivism compared with people sentenced through other courts. After 24 months, the difference in the rate of recidivism grew to 29 per cent.

KPMG said many of those coming before the Drug Court would otherwise face jail – a much more costly option for taxpayers. It would cost about $26,000 to put a participant through the Drug Court's programs for two years, KPMG said, compared with an average cost of $197,000 to imprison someone for two years.

Chief Magistrate Peter Lauritsen said magistrates would welcome the government's announcement, as they were required to sentence people based on what was available in their local area.

"It becomes a question of fairness and this is a major expansion of a very successful operation," he said.