A group of Maryland bills that would mandate the wearing of restraining belts in automobile front seats received the support here today of a broad, if unlikely, coalition that included homemakers, scrap dealers and car manufacturers.

Representatives of the Maryland Association of Women Highway Safety Leaders; the Auto Trade Association, an auto dealers' trade group; the American Automobile Association and the Institute of Scrap Iron and Steel were among nearly 30 supporters who spoke at a standing-room-only hearing before the Senate Judicial Proceedings Committee.

If a law is enacted, Maryland would follow New York, New Jersey and Illinois in requiring motorists to wear seat belts while in the front seats of automobiles.

For some witnesses at today's hearing the issue was fairly simple.

State Sen. Decatur Trotter (D-Prince George's), citing federal statistics showing that requiring the use of seat belts could cut down the number of accident fatalities by as much as half, asked the committee to approve a bill he sponsored as "an opportunity to save many lives."

He said that 663 motorists died in accidents in Maryland in 1983, adding that statistics show that only 12 to 15 percent of the state's drivers use seat belts, although they are standard equipment on cars now.

Sen. Frank Shore (D-Montgomery), a cosponsor of the bill, added that "statistics show it's almost impossible to be killed if you're wearing a seat belt and you're driving under 30 miles per hour," as most urban drivers do. That bill, also cosponsored by commitee Chairman Sen. Thomas V. Mike Miller (D-Prince George's), would fine violators $50.

Bills submitted by other officials would levy a fine of $25, the amount charged violators of a 1984 state law requiring use of safety seats to restrain children under 3 years old. Most bills under consideration would exempt motorists who can prove a medical reason for not wearing belts.

The seat-belt bills have attracted the support of many grassroots groups that lobbied for a child seat-restaint bill two years ago. The Maryland Extension Homemakers Council, for example, is planning to circle the State House Wednesday with a "human seat belt" of 250 persons to press the point.

But legislators said that other supporters of the legislation were motivated by the automatic restraint regulations issued by U.S. Transportation Secretary Elizabeth Dole last July. Those regulations would require such devices as air bags in all cars sold in the country by 1989, unless states with two-thirds of the country's population pass mandatory seat-belt laws meeting certain requirements.

Auto manufacturers and dealers thus have developed a keen interest in the Maryland legislation. A manufacturers-funded group called Traffic Safety Now passed out glossy pamphlets at today's hearings declaring, "There's no time to lose -- we need state belt use laws now!"

Several legislators took note of the auto industry's interest: Sen. Jerome Connell (D-Anne Arundel), criticized federal highway officials who appeared in support of the bill for placing the states in the position "of being a pawn between industry and the federal government."

"My concern is that we then become two-thirds of the population that exempts the auto manufacturers from installing the most effect safety mechanism, i.e. air bags," said Sen. Gerald Winegrad (D-Anne Arundel).

Opposition to the bills today was slight. Helen O'Leary, 65, a resident of Prince George's County, called them "absolutely Orwellian -- big brother at its worst."

Representatives of the scrap-processing industry, including I.D. Shapiro, president of the United Iron and Metal Co. in Baltimore, said the gas that propels the air bags is a carcinogen and dangerous to his workers, who grind up scrapped cars, air bags and all.

"It seems like we ought to take care of a problem at the beginning. We're at the end of the cycle," he said. Removing the air bags before processing would be too difficult and "even if we did take them out, what would we do with [them]?"