Two economic think tanks have said an annual wealth tax could yield at least €150m.

A research paper jointly published by TASC and the Nevin Economic Research Institute says such a tax would be an annual tax on net household worth. It would not be charged on companies.

A high tax free allowance of €1m would, the report's author said, ensure the tax would only apply to the top 2% of Irish households. Pension assets would also be exempted from the tax.

The report proposed a flat marginal tax rate set at a low level, but stops short of suggesting an actual rate. It said a rate of up to 1% is possible.

It said a tax rate of 0.6% on net wealth above €1m would yield 0.6% of GDP - equivalent to €150m, using what it said are very conservative assumptions about wealth distribution in Ireland.

The report's author, Tom McDonnell of TASC, said the main risks to be considered are high administration costs and capital flight. A wealth tax should have a low effective rate in order to minimise the risk of capital flight, it recommended.

It states that administrative cost is lowest where there are a minimum number of exemptions and reliefs from the tax. The basis for the tax should be self assessment, it added.

The report also said there is a general lack of good data on the distribution of wealth in Ireland. This makes it harder to make economic policy and to estimate tax yields in general. A forthcoming wealth survey by the Central Statistics Office - due next year - is a welcome development, the report said.

The report cited Central Bank research estimating aggregate household net worth in Ireland at the end of 2012 was €462 billion. This excludes the value of certain real assets such as vehicles and artworks.

France, Norway and Switzerland have taxes on net wealth, while Spain and Iceland have introduced temporary wealth taxes.