THE GST AND HOW IT'S CARVED UP BETWEEN THE STATES AND TERRITORIES
* The GST is Australia's general consumption tax, introduced by the Howard government in 2000.
* The 10 per cent impost on about half purchased goods and services raises about $57 billion a year.
* The commonwealth collects the tax and distributes the revenue to the states and territories using a typically bureaucratic named formula - horizontal fiscal equalisation.
* In plain English it's a social equity objective that recognises states have different capacity to raise revenue from their taxes and how much it costs each of them to deliver services and infrastructure.
* WA and the Northern Territory, for instance, are better placed to collect mining royalties; NSW and Victoria collect more stamp duty through higher house prices.
* Increasing the share for one state comes at the expense of others.
* WA is complaining now because it's receiving less than 40 cents for every $ its residents pay in GST - down from 79c in 2009-10 - at a time when its mining tax revenue has slumped.
* Some states and territories receive more GST revenue than their residents pay: NT $5.6 for every tax dollar; Tasmania $1.63; South Australia $1.28; ACT $1.24; Queensland $1.08.
* If revenue was distributed on a per-capita basis NSW would get nearly a third of the pie; Victoria a quarter; Queensland a fifth; WA 11 per cent.
* The PM has flagged a review that creates a floor share - somewhere between 50 and 75 cents - for all states. Except for WA, no state or territory's share has ever dropped below 82c in the $.
