BOCA RATON, FLA., DEC. 1 -- Sen. James R. Sasser (D-Tenn.) said today that if the United States gets into a shooting war in the Persian Gulf, President Bush would likely have to impose a tax surcharge to pay for the costs of the war.

"We can't sustain the expense of a full-blown war there with our present budget problems," said Sasser, chairman of the Senate Budget Committee.

An income tax surcharge of 10 percent was imposed in 1968 to pay for the costs of the Vietnam War, Sasser said.

Sasser, who played a key role in fashioning the recent budget deficit-reduction package, said a shooting war would quickly wipe out the package's estimated first-year savings of $41 billion. He said that over the next five years, the package is expected to reduce the deficit by a total of $496 billion, although substantial deficits are expected to continue for several years.

If a full-fledged war does not break out, Sasser said he believes that the Pentagon could continue its military deployments in Saudi Arabia under existing budget appropriations.

The Congressional Budget Office has estimated the cost of the Persian Gulf deployment at $12 billion to $30 billion for fiscal 1991, he said.

Sasser, who spoke today to the Securities Industry Association, said told reporters afterward that Bush would have to find additional revenue to pay for a full-fledged war because Congress would be unlikely to make any more budget cuts.

"We cannot continue to borrow to finance a war in the Middle East to protect the oil supplies of our friends in Japan and our friends in Europe," he said.

Sasser said that he had not discussed the surcharge idea with the White House or congressional leaders and did plan to propose the idea. He said, however, that he believes Congress would support a war surtax if Bush said such a tax was necessary to pay for the nation's military efforts.