If any of the 400,000 U.S. troops readying for war in the Persian Gulf thought they might be excused if they filed their federal income taxes a bit late, they can forget it.

An Internal Revenue Service spokesman said yesterday the April 15 deadline will not be waived for U.S military personnel mobilized for Operation Desert Shield, unless a shooting war breaks out.

But fear not, the IRS said there will be an efficient system for dispersing W-2 forms to those camped out in the Saudi desert and aboard ships in the Persian Gulf.

"We are working with the Department of Defense and we understand that DOD will deliver the W-2 over there," said IRS spokesman Henry Holmes. The Defense Department also will provide military lawyers on site to assist with tax questions. Conveniently, the IRS also has an office in Riyadh, Saudi Arabia.

Hostages and "human shields," the Americans held at strategic Iraqi military sites to deter U.S. airstrikes, do get more leeway. Their tax filings don't have to be mailed to the IRS until "the 15th day of the third month following their release," according to the IRS's six-page explanation of rules applying to Operation Desert Shield.

Defense Department spokeswoman Susan Hansen said that during the Vietnam War, troops in a combat zone received automatic tax extensions. If a shooting war erupted in the gulf, the filing and payment of taxes would again be temporarily suspended, she said.

If, however, the stalemate in the Persian Gulf persists, the following IRS rules apply:

Reservists and military personnel must file federal taxes or apply for an extension by April 15.

Special pay for hazardous duty is taxable.

Reservists called to active duty can get their interest rate on back taxes owed the IRS reduced to 6 percent (it is currently about 11 percent for others). In hardship cases and for families whose income has dramatically dropped because of the deployment, the payment of back taxes can be deferred without interest.

The IRS is suspending tax audits and collection actions against hostages held in Iraq as long as they are detained. Penalties charged during the detention will be waived if "reasonable cause" is proved. Relatives, friends or employers of those detained are asked to inform the IRS by calling 1-800-829-4351.

"We know that they are far away and some of the things they need to file are here," Ellen Murphy, IRS director of public affairs, said about the U.S. troops.

"We are trying to be as cooperative as possible. Obviously, when you have a group of 400,000 people, there are going to be some exceptions."