ANNAPOLIS, JAN. 7 -- Maryland transportation officials said tonight that all new highway and mass transit construction will be delayed at least 18 months unless state leaders approve an infusion of money through new gasoline taxes and motor vehicle fees.

Despite the warning, a special gubernatorial committee, which had conducted a two-month study, declined to make a firm recommendation to Gov. William Donald Schaefer on how to deal with a dramatic slump in transportation revenue.

Stephen Zentz, deputy transportation secretary, said the 45-day freeze on beginning new road projects that was ordered last month would have to be extended 18 months before revenue would be available under the current 18.5-cent-a-gallon gasoline tax. Such a delay would mean the state would miss two construction seasons, he said.

William K. Hellmann, a former transportation secretary who was chairman of the committee, said he was being practical in not calling for a vote, in view of the unflinching opposition to any tax increase by House Speaker R. Clayton Mitchell Jr. (D-Kent).

"I'm disappointed, yes . . . but raising taxes is a sensitive issue," Hellmann said, explaining the decision not to seek a vote at the committee's last scheduled meeting. "Why force an issue . . . when you know it's not going to get settled until some way into the {legislative} session?"

In ducking the issue, the committee threw it back to Schaefer, who once expressed hope that the panel would help build support in the General Assembly and statewide for new taxes to prop up a transportation fund that has dwindled along with the economy and gasoline sales.

The Department of Transportation asked the committee tonight to approve a five-year, $1.5 billion program that called for applying the state's 5 percent sales tax to the retail price of gasoline, increases in Motor Vehicle Administration fees and additional truck fees.

However, the three House members on the 15-member committee were under instructions from Mitchell not to support tax increases.

"Clay doesn't think there is a need for a gas tax increase," said Del. Charles J. Ryan (D-Prince George's), a member of the panel, noting that other parts of the state budget also have major shortfalls. "He asked us to look at the total needs across the board, not just go one step at a time."

Transportation Secretary James Lighthizer held out hope that some action can be taken after the General Assembly convenes Wednesday.

"The House guys have to follow the leadership line," Lighthizer said. "Obviously, it's very important, crucial, what the speaker's opinion is."

Before the committee adjourned, the three senators and the public-sector members of the panel spoke in favor of raising taxes to provide $1 billion to $1.5 billion for roads and mass transit through 1996.

"Assuming the governor introduces the legislation, I agree that $1.35 billion should be the minimum," said Sen. Laurence Levitan (D-Montgomery).