Treasury has estimated that capital gains tax exemptions on the family home will cost the budget well over $50 billion in 2015-16, with superannuation concessions costing almost $30 billion and GST exclusions around $21 billion.

Commonwealth Treasury's annual tax expenditure statement attempts to quantify how much revenue the Federal Government will forgo from various exemptions or concessions.

Negative gearing is not included on the list as it is considered a normal feature of income taxes, where only net income is taxed after various expenses have been deducted.

However, the total exemption of owner-occupied homes from paying tax on any capital gains made was estimated to be worth around $54.5 billion this financial year.

More than half of that figure is due to the 50 per cent discount on capital gains tax for assets that have been held for more than 12 months.

With any Federal Government highly unlikely to make home owners pay tax on any gains they make in the value of their family home, that leaves super, the GST and the capital gains tax (CGT) discount as the largest potential sources of revenue from reducing tax exemptions.

The 50 per cent CGT discount also applies to investor-owned properties which are subject to capital gains tax, and Treasury estimated that it will cost $6.15 billion this financial year.

A much bigger target than investor capital gains is superannuation.

Treasury estimated that the concessional tax rate on employer super contributions will cost the budget $16.25 billion.

Even if people change their behaviour in response to the removal of that concession, Treasury still forecast that the Government could gain $15.6 billion in revenue.

The concession on super fund earnings was estimated to be costing the budget $13.55 billion in revenue forgone this financial year, with the potential to recoup $12.6 billion if they were taxed equivalently to other income.

While it is unlikely that any government could completely remove any of the above concessions to realise the full revenue gain, Treasury's figures highlight how much money might be saved if they were made less generous.

Richard Denniss, chief economist with left-leaning think tank The Australia Institute, said these figures are important for the budget repair debate.

"Imagine you ran a restaurant and you let some of your customers eat for free, all of those free lunches would cut into your bottom line," he argued.

"Well, when you're a government and you let some people pay a lot less tax than others then that has a real cost to the budget, and the tax expenditures statement is the document that tells us what all those loopholes and concessions are worth."

Amid the ongoing debate about lifting the rate of the GST, the Treasury figures reveal how much various exemptions from the tax are costing at the current 10 per cent level.

The exclusion of fresh food was estimated to be worth $6.8 billion of lost revenue, the education exemption $4.2 billion, health $3.7 billion and "financial supplies" $3.25 billion.

Other exemptions for child care, aged care and water/sewerage were each estimated to cost closer to a billion dollars.