The Internal Revenue Service is previewing the new tax forms that 101 million Americans should begin receiving in the mail next week.

The IRS traditionally mails out the 101 million tax packages after Christmas in order to avoid the holiday crush but allow taxpayers plenty of time to begin preparing their returns, which are due on April 15.However, some taxpayers report they have already received the new forms.

IRS officials emphasized that the 1988 tax packages contain few changes from the forms taxpayers used last year.

Last year, taxpayers for the first time filed returns that reflected the more than 2,000 changes made by the Tax Reform Act of 1986.

Despite the many changes on those forms the IRS said most taxpayers were able to file accurate forms promptly and received their returns on time. The IRS said that most of the changes this year would be so subtle that they would likely go unnoticed by taxpayers.

The change with the biggest impact reflects the final reduction in personal tax rates mandated by the sweeping 1986 tax overhaul law.

However, those reductions are incorporated in the tax tables and do not show up in the forms at all.

IRS officials said other changes had been made to clear up confusion raised by last year's forms. One area where clarifying changes were made involves the standard deduction. Because of confusion, some taxpayers last year failed to enter their correct standard deduction, thus lowering the refund they should have received.

IRS officials said those mistakes were caught.