It's early days in the preparations for the budget but it is difficult to see what is being achieved by the mixed signals being sent out over property tax.

The tax has been recommended as a necessary recalibration of the tax system away from the volatile and pro-cyclical reliance on transaction and spending taxes such as stamp duty and Vat.

Income from both sources – stamp duty on housing sales alone generated €1.3bn in 2006 – has all but disappeared with the crash, leaving us with a €20bn deficit to reduce while at the same time trying to find the money to pay for respite services and hospital wards.

A year ago, the Commission on Taxation spent many pages explaining how a fair form of property tax, based on site valuation with exemptions for those on low pay or social welfare, could be framed.

The IMF and the ESRI have added their support to the idea, along with a host of independent academic economists, including the governor of the Central Bank Patrick Honohan, who has highlighted the structural folly of over-reliance on stamp duty and Vat as the pump that inflated the property bubble.

Yet time and again, when either Taoiseach Brian Cowen or finance minister Brian Lenihan have been asked about a property tax on "principal residences", as Ivor Callely might say, both men have fudged the issue.

Both say "nothing has been ruled in or out" as far as measures to cut another €3bn off our borrowings are deliberated.

The approach is in keeping with a long tradition of confidentiality over budget measures. But a move to property tax is different. This is a policy issue that needs debate so that its advantages and disadvantages can be clearly set out. It will affect about 1.8 million homeowners. But with one third of mortgage holders in negative equity and one in 25 more than three months in arrears, most people are looking for tax relief, not a further tax burden.

Some clarity would therefore be a help – and might even convince a proportion of doubters that it is necessary. Yet in the past two weeks we've had only confusion.

A couple of weeks ago, Brian Cowen extolled the simplicity of the €200 second-home tax, while days later, Brian Lenihan told backbenchers that no groundwork had been done by the Department of Finance to prepare for a property tax.

One of those backbenchers, Chris Andrews, felt confident enough to trumpet that it was now off the budget agenda.

Instead of laying out evidence-based options, Brian Lenihan has left everyone convinced that a property-related tax won't be logical or fair. It will be worked out on the basis of the crudest form of maths possible: x divided by y (where x = the hundreds of millions of a hole left in the budget after all other forms of revenue have been raided and y = the number of homeowners deemed eligible to pay.) It will probably add up to about €400 or €500 per household.

There will no doubt be some sort of exemption for homeowners who are jobless, low paid or in massive negative equity and mortgage arrears – and perhaps even a tax break for people who bought homes in the past five years and have already stumped up thousands in stamp duty.

But it's a safe bet that homeowners caught in the government's net will pay more tax on their family homes than the €200-a-property introduced for investors and wealthy people with holiday homes.

In the interests of even greater deception, it might not even be called a property tax. What about an eco-friendly 'service' charge so that the Greens take some of the stick?

This is not about tax policy or economic reform. It's lazy and once again, it treats the electorate with contempt.