ANNAPOLIS, AUG. 13 -- The rapid rise in gasoline prices after Iraq's invasion of Kuwait will make it politically difficult for Maryland to boost its motor fuel tax next year, key legislators said today.

A special 23-member committee of the General Assembly, beginning an inquiry into gasoline price increases, was told by the American Automobile Association that prices in Maryland jumped an average of 7 to 10 cents per gallon in the seven days immediately after Iraq's attack, the steepest one-week rise in state history.

Those increases, along with others almost certain to follow an international embargo on Iraqi and Kuwaiti crude oil, could derail expected attempts in the legislature to raise the state gasoline tax by 5 to 10 cents a gallon to pay for transportation programs. The current 18 1/2 cents tax on each gallon sold at the pump is the 10th highest in the country.

The administration of Gov. William Donald Schaefer, which pushed through a 5-cent gasoline tax increase in 1987, has privately been discussing with legislators another hike next year, after this November's elections.

"This upsets things," Del. Tyras S. Athey (D-Anne Arundel) said of the Middle East crisis.

"We were all convinced before that we needed an increase if we were going to make improvements," said Athey, chairman of the tax-writing Ways and Means Committee. While saying that a tax increase is not "impossible," he added that the current crisis "is certainly going to have a big effect."

Del. Gary R. Alexander (D-Prince George's), co-chairman of the committee investigating oil prices, said lawmakers considering a tax increase on gasoline will "have to look at the effect on consumers."

House Speaker R. Clayton Mitchell Jr. (D-Kent) said, "This makes it very, very, very difficult to even consider something like {a gasoline tax increase}. Thankfully, that's a ways down the road."

Schaefer, who appeared before the committee to urge consumers to conserve energy, told reporters afterward that he does not think that gasoline price increases prompted by the Middle East situation will necessarily preempt a tax increase.

Although not saying that he supports raising taxes, Schaefer said that consumers would differentiate between a tax increase and higher prices caused by the loss of some overseas oil.

"Are we going to have new roads, repair bridges and have mass transit?" Schaefer asked. "The public understands that we're close to being out of money with our great road program. We've built roads in Montgomery County and Prince George's County and Anne Arundel County.

"This is a bad time to be talking about taxes, but people want to have roads and bridges repaired."

Earlier, Schaefer said there is no evidence of panic buying or hoarding of gasoline in Maryland. He said he does not now need to use his emergency powers to allocate or ration gasoline supplies.

During the committee's first session, state Comptroller Louis L. Goldstein said every refiner has increased prices, but he added that prices appeared to have stabilized in the past week. He also said demand for gasoline has been dropping in Maryland, down 6.7 percent from May to June, and that supplies remain adequate.

"I blame it on the big oil companies who have taken advantage of the situation as they have in the past," Goldstein said.

Goldstein, who has surveyed retailers and oil companies, told the lawmakers they may want to consider legislation that would give the Maryland Public Service Commission the power to control oil companies' price increases.

Michael McDonald, executive director of the Maryland Petroleum Council, said world oil prices had been rising before the Iraqi annexation of Kuwait. And, despite increases that have been posted, he said, not all has yet been passed to consumers.