Many court fines have fallen below inflation, with penalties for two thirds of the most common offences now worth less than two decades ago.
Australian-first analysis by Victoria's Sentencing Advisory Council looked at how fines issued by the state's Magistrates Court over a 19-year period compared with fine guidelines and inflation over that time.
It revealed financial penalties for 23 of the 30 most common offences had not kept up with inflation, including driving with a suspended licence.
The median fine for that crime stayed at $500 between July 2004 to June 2023, meaning the real value had fallen 37 per cent.
The remaining seven of the 30 most common offences had largely kept pace, the report found, including traffic offences such as stopping in a no-stopping area and failing to register a dog or cat.
The report noted courts were not bound by maximum fines, but instead their "north star" was maximum penalties, which could include imposing community correction orders or ordering a person to pay legal costs.
It did not offer definitive reasons why the value of some fines dropped and others had not.
When breaking down the fine for driving with a suspended licence, the report noted some stakeholders had queried whether the value decrease was due to more serious offenders receiving additional penalties such as prison, while less serious offenders received the fines.
The inflation analysis focused on Victoria, but said penalties for crimes varied across the nation, as each state and territory used their own guidelines to set maximum fines used in sentencing.
Victoria, the ACT and Queensland use penalty units which peg a certain dollar amount to a number of units set out by the Treasurer, in a system designed to make sure punishments change at the same time for all offences.
The Northern Territory and the Commonwealth increase penalty units based on a formula linked to the consumer price index, while Tasmania uses a mix of both.
NSW mostly uses the same system but has only upped the value of a penalty unit once since 1994 and has the lowest in the nation, currently $110, although the state regularly increases fines for traffic offences.
South Australia and Western Australia tend to set out maximum fines in dollar terms with some exceptions.
Sentencing Advisory Council director Stan Winford said the analysis raised some challenging issues in Victoria.
"One of the purposes of imposing a fine is to deter similar offending in the future - if the values of fines are declining, then arguably they are also losing some of their effectiveness as a deterrent," he said.
Mr Winford argued it would be difficult for sentencing courts to apply incremental changes to fines and maximum penalties were just one consideration in handing out punishment.
"Sentencing is more complex than that," he said.
"It involves courts balancing many considerations to determine a sentence that is appropriate in the circumstances of each case."
It follows an Australian Institute report claiming Australia's traffic fine systems are "criminalising poverty", calling to make fines proportional to a driver's income.
The think tank said while traffic fines were annoying for higher income earners, it could mean those on lower incomes were forced to choose between essentials or paying off the penalty.
In 2020, NSW offered a 50 per cent discount for people on government benefits who earnt certain fines, however elsewhere penalties are uniform across a jurisdiction regardless of income.
