The Institute of Chartered Accountants in Ireland (ICAI) has written to the Minister of Finance asking him to reconsider part of his decision on changing the timing of the tax year.

The ICAI, of which Mr McCreevy is a member, wants him to consider - at least - phasing in the proposals to bring back filing times and payment times for taxes.

The planned move brings the tax year and the calendar year into line. This was first mooted in December 1998 but was put off because of the difficulties firms were experiencing in the run up to the year 2000. It will now be implemented from January 2002 to allow systems to be changed over to the new euro notes and coins at the same time.

However, the move has implications for filing and payment dates. Preliminary tax will be paid in September 30th in the year of assessment, which is a slightly longer deadline than now. However, files will have to be returned by June 30th the following year which is a significant shortening of the nine months currently allowed.

Even a gradual phasing in of the proposal over a number of years would allow tax practitioners and taxpayers to get used to it, a spokesman for the association said.

The institute's tax spokesman, Mr Kieran Ryan, said there was a rational basis for the decision, which follows the practice of many other developed countries. "However, at the moment the unavailability of adequate staff is stretching many practices' ability to meet existing deadlines. The prospect of having to do the same work in a shorter time frame, with a tighter labour market, is a very serious concern."

The proposal is likely to have a bigger impact on smaller practices than on the large concerns. Mr Ryan added that consultation could lead to some workable proposals. "What nobody wants is a situation where we get hastily prepared returns which would be less reliable and would lead to more correspondence with the Revenue," he added.