The increase of 12 cents a gallon in federal taxes on gasoline included in the new budget package probably will do far more to increase federal revenue than it will to decrease U.S. gasoline consumption, oil economists said yesterday.

The idea of a higher federal gasoline tax has been proposed in the past as a way to force Americans to drive less, reducing dependence on foreign oil and lessening pollution.

The relatively modest tax increase proposed yesterday, however, is unlikely to make a significant dent in U.S. gasoline use, experts said, particularly in light of the already large increases in gasoline price in the two months since Iraq invaded Kuwait.

"This is not primarily to reduce consumption; it's primarily a revenue measure," said John Lichtblau, executive director of the Petroleum Industry Research Foundation, a New York think-tank partly funded by the oil industry. "In an inflationary period, a 10 percent increase in the price of gasoline isn't all that much."

Lichtblau said the effect of the higher taxes could be further blunted if world tensions ease and crude oil prices recede in coming months, reducing gasoline prices. In that case, he said, "You might end up with gasoline prices approximately where they are now by next July because of the 12 cent {tax} increase."

Still, Lichtblau said, there could be a limited impact on gasoline use. "You've already seen a reduction in gasoline consumption because of what has happened since early August. This is likely to reduce it further."

Arnold Safer, an economist at the Energy Futures Group, a Washington consulting firm, said: "If it goes in immediately, it's going to be a significant jump in prices. ... It's going to help dampen demand {and} might save a little bit on imports."

Philip K. Verleger Jr., an energy economist at the Institute for International Economics in Washington, estimated that the higher tax would reduce U.S. gasoline consumption by 1 percent the first year it is fully in effect -- less than 100,000 barrels a day, compared with consumption now of more than 7 million barrels a day. Over time, he said, the impact might expand to 300,000 barrels a day.

The Office of Management and Budget estimates that the increased tax on gasoline will bring in about $12 billion a year in federal revenue and contribute about $56 billion in all over the next five years. The increased tax will add about 0.2 percent to the nation's inflation rate.

Gasoline prices are up more than 20 cents a gallon since Aug. 1 and still rising because of the doubling of crude oil prices since Iraq invaded Kuwait Aug. 2. Given that rate of increase, experts said, the phased-in gas tax will probably seem like just another price increase if it is approved by Congress.

Under the plan, the federal gasoline tax will rise from 9 cents a gallon to 14 cents on Dec. 1 and to 19 cents on July 1. A tax of 2 cents a gallon on all petroleum products is to go into effect Jan. 1 under the plan. Experts said the separate petroleum tax, which also applies to such products as heating oil and jet fuel, is too small to have an appreciable impact on consumption.

Budget Director Richard Darman said yesterday at the White House being implemented in phases because of other recent sharp price increases.

While economists said the effect of the increased taxes would be relatively modest, consumer advocates and others criticized it yesterday as unfair to poorer Americans and suggested it could significantly worsen an economy already battered by a sharp increase in energy costs.

"They've decided on a regressive gasoline tax at a time when people are paying an extraordinary amount of money for higher {gas} prices," said Edwin Rothschild, director of Energy Action, a Washington-based consumer advocacy group. "This is a prescription for further recession, as if we didn't have enough."

Rothschild said the higher tax would put a particular burden on Americans living in rural areas who have no choice but to use their cars for transportation because of a lack of mass transit, as well as hurting poorer Americans who tend to own older cars that get poor mileage compared withnew models.