Tax evaders have been given six months to get their affairs in order in relation to offshore assets under the Finance Bill.

The measure is likely to lead to a cash windfall for the Revenue between now and the end of April next year.

The Bill, published Thursday by Minister for Finance Michael Noonan, intorduces a clampdown on tax defaulters.

Revenue will no longer allow any mitigation of penalties in settlements relating directly or indirectly to offshore assets on which tax has been evaded even where the taxpayer makes a “qualifying disclosure” to the Revenue.

Until now, anyone approaching the Revenue voluntarily was able to avail of lower penalties on the tax owing. Penalties could be reduced by up to 50 per cent in such cases. A qualifying disclosure requires a taxpayer to approach the Revenue before the tax authorities start any audit of their tax affairs and disclose in writing any tax they might owe along with interest due on that money.

The new rules come into force on May 1st, giving taxpayers currently in default a six-month window to put their affairs in order.

The Bill also amends how the quarterly published list of tax defaulters is presented.

Defaulters who have reached a settlement with the Revenue on taxes owing along with interest and penalties but who have not paid the money due under that arrangement may now have that noted in the list .

The current requirement for the Minister for Finance to increase the limit below which no details are published every five years is being changed. In the future, the limit will be increased “from time to time” at the discretion of the Minister. At the moment, the publication threshold is €33,000 and only settlement in excess of this amount are mentioned in the published list.

Where defaulters have made a qualifying disclosure – which exempts them from publication and mitigates any penalty - but have also been caught on other tax matters, only the settlement relating to tax issues they did not voluntarily disclose will appear in any published list.