This chart in a new IMF staff working paper caught my eye:

IMF tax expenditures

The chart shows that Australia has more tax expenditures – concessions or reductions for particular types of activity – than many comparable countries. There are significant difficulties in comparing these estimates across countries, because what counts as a “tax expenditure” depends on the benchmark you use, so I wouldn’t put too much emphasis on the fact that our estimate here is higher than Italy’s or America’s. But it is undoubtedly the case that we have a lot of tax expenditures. The Treasury’s numbers show that these are expected to grow over time, particularly tax expenditures related to superannuation. Those go overwhelmingly to high income earners, with top 1% receiving more government assistance for their retirement savings (in the form of super concessions) than the poor receive in the form of the age pension.

A government concerned about improving the structural budget position would start with examining these concessions.