Congressional tax writers from both parties and both chambers have told the Internal Revenue Service – and about 20 million taxpayers – not to worry about any new hit from the alternative minimum tax this year.

“We want to assure you that legislative relief is forthcoming so that no new taxpayers will be subject to the AMT for taxable year 2007,” said the letter sent Tuesday to acting IRS Commissioner Linda Stiff. It was signed by Senate Finance Chairman Max Baucus , D-Mont., ranking Republican Charles E. Grassley of Iowa, House Ways and Means Chairman Charles B. Rangel , D-N.Y., and ranking Republican Jim McCrery of Louisiana

Those four lawmakers still disagree sharply on the shape and scope of an end-of-year tax package, which also may include extensions of dozens of expiring tax provisions affecting individuals and businesses. The IRS starts printing forms in November and bases its actions on current law.

In 2006, about 4 million people paid the AMT, a levy created in 1969 that was originally designed to prevent the rich from using legal deductions and credits to avoid all taxes. The tax has never been indexed for inflation, however, and unless Congress acts, about 25 million people will be forced pay it in 2007, according to the Treasury Department.