Taxpayers have until the close of business today to tell the Revenue about offshore bank accounts or face the prospects of an investigation and, possibly, prosecution.

The Revenue has been inundated with disclosures in the days running up to the deadline, with 6,500 people contacting tax offices up to the end of last week.

Revenue chairman Mr Frank Daly told the Dáil Committee of Public Accounts last week that more than 10,000 people may contact the tax authorities over accounts held in other countries. To date, Revenue authorities have collected €184 million from some of those involved.

Up to recently, 3,500 people had come forward following notification from their banks of Revenue interest in the accounts. Towards the end of last week this figure jumped to 6,500.

Over the past month, 10 financial institutions have been sending up to 120,000 letters to customers who have addresses in the State but bank accounts outside the Republic.

While Revenue is reluctant to speculate on how much the trawl may eventually yield, it is expected to bring in substantially more than other recent Revenue investigations.

People who do contact the Revenue will have 60 days, until May 28th, to calculate and pay any tax due together with interest and penalties, which may be mitigated by the voluntary disclosure.

Those failing to make a voluntary disclosure of their liabilities by today face the prospect of penalties, interest, publication of their names and even prosecution.

A spokesman for the Revenue said that, with the postal dispute crippling mail services in large parts of the State, it was operating four dedicated fax numbers and was also accepting disclosures at any tax office.

However, there was no talk of the deadline being extended to allow for the dispute. The fax numbers are: 01 8277486, 01 8277780, 01 8277782 and 01 6474821.