The initial targeted tax relief to low and middle income earners was estimated to cost the budget $13.4 billion over the four years of the forward estimates. Larger tax cuts after the first four years increase the cost substantially. The government has estimated the cost to the budget over the whole 10 years to be $140 billion.

It is not just high income earners who are the big winners from these tax cuts. Once they are fully implemented in 2024-25, men will also be the big beneficiaries. Men will get twice the tax cut in 2024-25 compared to women (men will get about two thirds and women will get about a third).