A full property tax system would be fairer than a flat-rate property charge, according to new research carried out by the Economic and Social Research Institute.

It says a properly designed property tax would be able to exempt low-income groups, such as pensioners and those on social welfare, while charging more to those on higher incomes.

The ESRI has been exploring various options for a property tax.

In particular, the ESRI has been looking at what would be needed to raise the Taoiseach's target of €500m a year for a full property tax, compared with the €160m target for this year's flat-rate property charge.

It says an income-related property value tax could provide such a model, and would need to be set at an annual rate of €2.50 per €1,000 of house value.

Under this model, the bill would be less than €2 a week for the poorest 30% of households, between €4 and €7 a week for the next 30%, rising to €8 to €10 for the next 30%.

The top 10% of earners would pay close to €15 a week.

The ESRI says flat-rate charges are inherently unfair, as everyone pays the same regardless of income level or property value.