Tony Abbott’s call for a “mature” debate about federalism and the GST should be no shock to anyone. It was on the cards the moment the May budget revealed that funding to the states for health and education was to be cut by $80bn from 2017-18 onwards. But while a GST may help raise more revenue, the government must address the fact that any increase in GST will hurt the poorest the most – the same households targeted in the government’s first budget.

While a mature debate is always welcome, the timing of Abbott’s call is rather interesting. I guess a debate could only be had after winning office because in August last year, when the (inevitable and accurate) suggestions that a Coalition government would seek to raise the GST were made, Tony Abbott responded by pledging, “let me be as categoric as I can. The GST won’t change, full stop, end of story.”

Not so much the end of the story as an intermission, it seems.

So was a mature debate on the carbon price or the mining tax never needed while Abbott was in opposition?

Similarly, we can dismiss calls by the prime minister, such as those he made in a speech to the Business Council of Australia when he invited “the Labor party, the state governments to join Team Australia and think of our country and not just the next election” as pure political posturing.

Tony Abbott was certainly thinking about the next election last August, and given that he is using the moronic work-shopped term “Team Australia”, which previously had only applied to national security, it’s abundantly clear he continues now to think only of the next election.

His calls for bipartisanship on terrorism seem to have shifted to a call for the same bipartisanship on economic issues.

But this hypocrisy and politicisation is not reason enough to dismiss the debate about the GST, neither is it the only problem the government needs to counter.

It must also prosecute Tony Abbott’s assertion that he believes in “lower, simpler, fairer taxes”. For low taxes are not necessarily fairer, neither are simpler ones, and fairness does not end with taxation – indeed it is just the start.

And given the government’s first budget was overwhelmingly targeted at hurting poorer households over wealthier ones, it appears that when the prime minister talks about fairness he’s not talking about equality.

I have written a number of times that we need to discuss changing the GST. Indirect taxes such as the GST are generally regarded as more efficient than income tax. But what you gain in efficiency you lose in equality.

Regardless of what you earn, you pay the same amount of GST on an item. And because poorer people spend more of their income on goods and services than do wealthier people, a GST is invariably regressive – it hurts you more the less you earn.

There are two ways to change the GST. The first is to just raise it. But this does nothing to make it simpler. The exemptions for certain foods would remain. It would also fail to alleviate the fact that we now spend more of our income on goods and services not covered by the GST than we did when it was introduced.

So any reform to the GST must involve broadening its base by including items such as fresh food, water and sewerage, and health and education expenses.

But the most recent household income and expenditure data, released earlier this month, shows that lower income households spend more of their income on these items than wealthier households do:

Only on education expenses do wealthier households spend about the same of their income as median income households. But for all other items – food, water and sewerage, and health – including them within the GST would automatically make life harder for poorer households.

The data even shows us that single parents and pensioners would easily suffer more than other types of households:

The only way to alleviate this is by reducing income tax and/or increasing welfare.

This is tricky because currently our tax and welfare system has an important role in reducing inequality:

The wealthiest quintile (20%) of households receive 46.2% of all household income compared with just 4% going to the poorest quintile. But after counting welfare such as pensions, family tax benefits and unemployment benefits, the poorest quintile has 6.9% of total income, with 42% going to the richest.

Once taxes are taken out, because the wealthiest pay more of their income in tax, their share of income falls to 39.1%, while the poorest quintile has 7.7%.

So income tax and welfare are vital to redistributing income to ensure some degree of equality. Yet it is this precise area that Joe Hockey and Tony Abbott have targeted with their suggestions that people on welfare are leaners.

And taxation and welfare is not where the story ends. Public services like education and health provide households with what is called “social transfers in kind”. For example, when you get education at a public school you receive a service that is worth the money you would otherwise have had to pay.

Not surprisingly, the poorest households get more services than the richest.

Once these are taken into account, the wealthiest quintile of households receives 34.5% of total income and the poorest quintile now gets a 10.8% share of total income.

And most of the work redistributing income is done through these social transfers:

The poorest 20% of households get on average $20,970 a year from direct benefits, but $27,237 from social transfers in kind.

And yet, just as with direct benefits, the Abbott government has targeted health and education spending either by cutting it or by attempting to introduce payments such as the GP co-payment – all of which reduces the social transfer amount.

The Coalition argues the GST needs to be reformed in order to pay for health and education expenditure, except it was also the Coalition that announced it was cutting these expenditures too. It has also announced it will abandon the needs-based education funding model that reduces inequality in that social transfer.

The federation might need fixing and the GST should be examined, but the impact of GST changes on equality, as well as on the efficiency of the tax system, must be considered.

For the past 12 months the government has attacked the poorest households for accessing welfare, for being unemployed, for being on disability support pensions and for using services such as health care without paying up-front for them.

Now the government would have us believe they would change the GST and use welfare and social services to redress any added burdens?

Sorry, but you can’t just talk about fairness in a speech and think we’ll forget all your actions.