Accountants estimate that hundreds of thousands of taxpayers are still awaiting tax bills - even though they sent in their tax returns by the first deadline, on 30 September. If payments are not made by 31 January, the Revenue will demand a surcharge worth 5 per cent of the tax owed.
The Revenue promised last year that taxpayers who returned their forms by that date would get a tax bill before 31 January. But there are now widespread complaints that taxpayers are being left with too little time to pay their bills.
A spokeswoman for the Revenue said: "If taxpayers are still receiving tax bills we apologise for that because it was our intention that they should have them for the beginning of this month."
The Revenue said it was reviewing its arrangements for posting material en masse in the future. It claims the problem is confined to tax agents who have promised to handle every detail of their clients' affairs.
There are an estimated 3 million people who have still not yet returned their assessment forms and the Revenue forecasts that up to 1.3 million may face surcharges.
But evidence from taxpayers suggests those who sent in tax forms before 30 September are also getting their tax bills late. They face interest on their tax bill as well as a 5 per cent surcharge.
Chas Roy-Chowdhury, senior officer at the Association of Certified Chartered Accountants, said: "A lot of people who got their tax bills in before 30 September are still only getting their tax bills now. It is cutting things a bit fine."
The Association of Certified Chartered Accountants yesterday wrote to the Inland Revenue urging officials to show flexibility when payments were late. "The matter has been dealt with in a less than expeditious manner. We want to know where the Revenue stands on late payments resulting from the delays," said Mr Roy-Chowdhury.
The Revenue spokeswoman said taxpayers were free to appeal if they were surcharged for being late with their first payment. But there would be no waiving of interest charges for being late. "If a taxpayer feels there is some reason why we should have got to them sooner they can make an appeal against any cost being levied. But the fact that they don't have their tax bill need not mean they cannot make the payment," she said.
The Revenue admitted it had problems with its computer system for processing self-assessment accounts, designed by American computer giant EDS.