New laws to cut sentence discounts for serious offenders who plead guilty in South Australia are set to pass state parliament.
Attorney-General Vickie Chapman says the government has received a commitment that the Labor opposition will back the new measures which cut the top discounts from 40 per cent to 25 per cent for early pleas.
The legislation also requires the courts to consider a number of factors when determining how much a sentence should be cut including whether the person concealed their crime, the strength of the case against them and if the facts were disputed in any way.
Discounts on sentences for major indictable offences, such as manslaughter, causing death by dangerous driving or rape, will now range from five to 25 per cent, depending on the time of the guilty plea.
Ms Chapman said the bill was expected to be put to a vote in the upper house on Tuesday and once passed would be enacted as soon as possible.
It includes transition arrangements to deal with people already before the courts who may have just entered a plea or who are about to.
She said the 40 per cent discount, first proposed by the previous Labor government in 2010, was always too much and was more lenient than any other sentencing regime across the country.
"That was completely unacceptable to us then, and it remains so now," she said.
Ms Chapman said there would be a cost to the changes with offenders potentially spending more time in jail.
But she said that had to be balanced with public expectations on what period some people should spend behind bars.
The government's changes reflect recommendations from a recent review of SA's sentencing laws by former Supreme Court justice Brian Martin.