Wiktionary
n. (context Australia legal English) an amount, used as a basis of a penalty fine, which can be adjusted by the government without the need to pass new legislation.
Wikipedia
In Australian law, a penalty unit (abbreviated as PU) is an amount of money used to compute pecuniary penalties for many breaches of statute law. Fines are calculated by multiplying the value of one penalty unit by the number of penalty units prescribed for the offence.
The different jurisdictions that make up Australia (the Commonwealth and the states and territories) each have their own penalty units. The value of a penalty unit, and the manner and frequency of varying that value, differ from state to state, and there are also federal penalty units that apply only to federal offences.
In the state of Victoria, the value of a penalty unit is the amount fixed with respect to a financial year by the Treasurer by notice published in the Government Gazette under the Monetary Units Act 2004. The penalty unit rate is fixed at . Therefore, a fine defined as 100 penalty units would incur a penalty of $15,546 (rounded to the nearest 10 cents). One penalty unit in New South Wales is $110. One penalty unit in Queensland is $121.90
In the state of Tasmania the value of a penalty unit is adjusted for each financial year based on consumer price index (CPI) movements in the previous year, and published in the Tasmanian Government Gazette before 1 June for the next financial year. In the 2017 financial year it is $157.
Under Australian federal law a penalty unit for an individual is $180 .