NEW YORK (CNN/Money) – Forget tax reform for a moment. Of more immediate concern to lawmakers this week is whether they'll extend a number of tax breaks, most notably investment tax breaks and AMT relief.

Specifically, they are considering extending President Bush's tax cuts on capital gains and dividends through 2010 (the tax rates on gains and dividends are set to increase after 2008); and extending the "patch" for the alternative minimum tax (AMT). That patch would prevent an additional 16 million taxpayers in 2006 from falling prey to the tax, which disallows many key breaks available under the regular income tax.

Proponents of extending the lowered investment tax rates for 2009 and 2010 argue that investors and businesses have come to expect them, that they've encouraged economic growth and jobs creation, and that not extending them might adversely affect the economy and stocks.

Opponents say it's hard to justify an extension of a tax break that disproportionately benefits higher income taxpayers when lawmakers, under pressure to reduce the deficit, are also proposing to cut spending on programs like Medicaid and food stamps, which affect the poor and working poor.

Proponents of extending the AMT patch argue that the tax is unfairly and increasingly targeting middle-income taxpayers, not the wealthiest for whom the tax was originally intended. And unless and until the tax is repealed or permanently fixed, temporary relief needs to be put in place, which lawmakers have done annually.

Both the House and Senate committees charged with tax policy are expected to present their tax bills this week. But given developments so far, it looks like their bills might be very different from one another, which will make the reconciliation process between the two more complicated, said Helena Klumpp, news editor of Tax Notes, a tax policy and news magazine.

Rep. Bill Thomas (R-Calif.), chairman of the House Ways and Means Committee, suggested last week that he might take a pass on the AMT patch for now in favor of the investment tax cut extension.

Reports have suggested that part of Thomas' strategy might be to build support and momentum for the repeal of AMT, a key proposal in the president's tax reform panel's final report to Treasury.

Technically, lawmakers can pass an AMT patch anytime up to Dec. 31, 2006, and have it apply to tax year 2006. But that puts taxpayers who don't know whether they'll be subject to it in an awkward position come Jan. 1, 2006, tax analysts say, because they won't know whether they will be entitled to key deductions and credits that are available under the regular tax code but not under AMT (e.g., the federal deduction for state and local taxes on income and property).

Meanwhile, Senator Charles Grassley (R-Iowa), who chairs the Senate Finance Committee, has indicated he would like to include as many tax breaks as possible, including extension of the AMT patch, and offset their costs by various revenue raisers.

On Tuesday afternoon, a summary of Grassley's proposed Tax Relief Act of 2005, was released. Among the tax breaks it includes are:

• An extension of the AMT patch through 2006. That is, AMT income exemption amounts would remain at $58,000 for married couples filing jointly and $40,250 for single taxpayers.
• An extension of the lower tax rates on capital gains and dividends but only through 2009, not 2010. If approved, capital gains and dividends would continue to be taxed at 15 percent (5 percent for low and middle-income taxpayers, reduced to 0 percent in 2008).
• Extension of the saver's credit through 2009. The saver's credit provides a federal tax credit to low-income taxpayers for contributions they make to 401(k)s, 403(b)s, a variety of IRAs and other qualified retirement plans.
• Extension of the tuition deduction through 2010. The above-the-line deduction was created by the 2001 Tax Relief Act for qualified higher education expenses. It's due to expire at the end of this year.
• Extension of the state and local sales tax deduction, which lets taxpayer choose between taking an itemized deduction for their state and local income and property taxes or an itemized deduction for state and local sales taxes they pay. Originally in place for just tax years 2004 and 2005, Grassley proposes extending it for 2006.
• Various tax relief provisions for victims of Hurricans Katrina, Rita and Wilma.