Now that our Prime Minister has all but killed off a GST hike (although watch this space) he will need to look at everything from superannuation to capital gains to fix our budget problems, writes Ian Verrender.

Mark Twain only got it half right.

Taxes may be one of only two certainties in life, but tax hikes are certain death for politicians - a truism that certainly has begun to occupy the minds of those on the front bench.

That's why, when it comes to the vexed issue of tax, "everything is on the table" and any tax changes will be neutral. At least, that was the message until yesterday when the GST suddenly slipped off the table.

At some stage, however, the Turnbull Government will have to face up to the inescapable fact that if the deficit is to be reined in, taxes must rise.

The federal budget has a "structural" deficit. As opposed to a cyclical downturn, this is not a temporary phenomenon that will right itself once conditions improve.

It began with the global financial crisis in 2008 when capital gains tax revenues plummeted and the corporate tax take dived. The situation has deteriorated dramatically since the last election as spending levels soared under the Abbott-Hockey regime and tax revenues began to tank with the fall in commodity prices.

Australians are faced with two rather bleak options over the medium to long term: either we pay more for the services we expect to receive, or we elect to receive less.

Neither option is particularly palatable to a government facing re-election. It's a question of who you can afford to least upset.

Nor are they easy. An ageing population, elevated unemployment levels and infrastructure demands to accommodate a growing population give little leeway to any government when it comes to reining in spending.

Then there is the question of maintaining economic equilibrium. Our economy is facing significant challenges, financial markets are in a state of almost constant upheaval and global growth prospects are diminishing.

A heavy handed approach to fiscal matters at such a delicate time runs the risk of backfiring. A tight fiscal policy would dampen demand, damage growth prospects and ultimately could result in a bigger deficit.

Generally speaking, spending cuts tend to impact more on lower income groups while tax hikes hit the wealthy. Not surprisingly, the Abbott government's first budget - which focused almost entirely on spending cuts - was deemed grossly unfair.

Given most Australians are in low and medium income groups, the first Hockey budget was a political disaster, bringing the new Government's honeymoon period to such a spectacular end.

That's why the other side of the ledger - tax - is now the talk of the town.

Given he's now abandoned the idea of a tax White Paper and all but killed off a GST hike, here's a quick rundown on Malcolm Turnbull's tax options.

GST

Don't expect this to go away any time soon, regardless of the Prime Minister's preferences. For when it comes to tax, despite all the talk of reform, never underestimate the power of self-interest.

That's why, for the corporate sector, tax "reform" involves cutting the company tax rate, presumably so there will be less incentive to spend so much on specialist accounting firms who can shift earnings offshore to avoid paying tax altogether.

The business lobby is one of the most vocal proponents of a hike or a broadening of the Goods and Services Tax, primarily because it wants the increased revenue to fund a company tax rate cut.

The GST is a very effective tax. It raises vast amounts of revenue, and at lower levels, tends to have minimal impact on consumption.

Raising it, or broadening it to include things such as fresh food, health and education, is the easiest option for Treasurer Scott Morrison.

But it has one major drawback. It is a regressive tax, which means it has much greater impact on low and middle income earners who spend a greater proportion of their income just getting by. That's why it is the tax of choice from the rich.

Those in favour argue this problem can easily be overcome by compensating lower income groups. That's true. But as the carbon tax illustrated, a tax rebate at the end of the financial year will never obliterate the outrage driven by price hikes on a daily basis.

Not only that, tinkering with compensation reduces the tax's efficiency, makes the system more complex and adds to the dreaded "tax red tape".

State premiers of all persuasions have also argued strongly in favour of a GST hike. Why? That's easy. They end up with the bulk of it. There is a formula in place that divvies up the GST between the states so they don't have to go cap in hand to Canberra. There's that self interest kicking in.

Superannuation

If you want to talk fairness and fix the budget, this is a no-brainer. According to Treasury, taxing superannuation contributions at the marginal rate, rather than the flat 15 per cent now in force, would add $17.7 billion this year.

It would also result in a mass desertion of the Coalition's most rusted on supporters and a backbench revolt.

But the current system delivers the biggest tax breaks to those who earn the most, costing the budget about $25 billion this financial year.

A less radical option would be to give all taxpayers a 15 or 20 per cent discount on their top marginal rate, increasing the tax flow into Canberra, improving fairness and retaining an incentive to save for retirement.

Land tax

Tax breaks on the family home, the last truly tax free investment for ordinary Australians, is costing the budget about $55 billion a year. At least that's what Treasury reckons.

And the property price boom is only making it worse, given the huge capital gains since 2012 runs the risk of creating an underclass of Australians who will never own property without an inheritance.

Introducing a land tax would go some way towards rectifying that inequity. But it would require agreement from state governments to abandon stamp duties on property transactions. And given the entrenched position of home owners, the political cost of such a move would be enormous.

Capital gains

Those who earn an income from investments pay half the tax of those who earn an income from toil. Fair? Hardly.

Not only that, anyone earning an income from interest bearing deposits has to pay the full rate as well.

Not surprisingly, there is a push either to include interest in the discount, or to reduce the 50 per cent discount on capital gains.

Such a move would also limit the attractiveness of negative gearing, where investors use loss making ventures to reduce their income in the hope of picking up capital gains.

Easy options? Not on your life. Maybe Mark Twain was spot on.

Ian Verrender is the ABC's business editor.