The House Judiciary Committee today approved legislation requiring that youths under 18 who are convicted of drinking, buying or possessing liquor lose their drivers licenses for at least one month.

The approval of this measure, which committee members said would provide a strong deterrent to teen-agers drinking, effectively blunted the drive to raise the state's minimum drinking age to 19, although the legislation raising the drinking age has not yet been formally killed.

"To have teen-agers realize that their most cherished privilege could be taken away," said Montgomery County Democrat Joel Chasnoff, would prove to be a "clear deterrent" to youths tempted to lie about their age in order to purchase liquor or to accept liquor bought for them by their older friends.

"If these kids in high school understand that they're going to have their drivers licenses suspended, they won't participate in this nonsense," said Baltimore County Democrat Charles E. Kountz, who abandoned his advocacy of the higher drinking age after the committee approved the alternnative measure.

The final 14 to 2 vote approving the legislation requiring mandatory suspension of driver's licenses failed to reflect several committee members' opposition to an automatic penalty that leaves a judge no discretion in sentencing.

"There are so many degrees of culpability in this," argued John W. Wolfgang, the committee's vice chairman. "I can imagine a situation where there are four teen-agers in a car and one of them has a can of beer and all of them lose their liceneses . . . "You've got to give someone some discretion."

This argument, however, was disputed by some of Wolfgang's colleagues who said that unless the suspension of driving privileges was automatic, the measure would be ineffectual.

Under present Maryland law, any one 18 or older may buy beer and wine, but a person must be 21 before he can buy distilled liquor.

In past years, efforts to raise the minimum age for beer and wine consumption to 19 have failed, in large part because of the steadfast opposition of Joseph W. Owens, a Montgomery County Democrat who chairs the House Judiciary Committee.

However, in the wake of a pickup truck crash near Fort Meade last summer in which 10 teen-agers were killed, the legislation seemed to be sweeping through the General Assembly on a wave of emotional arguments about the need to curb widespread drinking among teen-agers. The driver of the pickup truck, 18-year-old Alan B. Cole, had been drinking before the accident.

Until today, the bill raising the minimum drinking age seemed to have a good chance of success in the Judiciary Committee despite Owens continued opposition. When a straw vote was taken on the issue Wednesday 11 members of the committee voted in favor of the proposal while 10 opposed it.

Since the legislation already had the support of Gov. Harry Hughes and House Speaker Benjamin L. Cardin, it seemed at that moment that it would be approved in committee and sent on to enactment in the full House with little difficulty. The state Senate had already approved the measure.

But after the aproval of the alternative proposal, which is contained in a measure decriminalizing all state liquor laws for minors and adults, Del. Lountz switched his position and voted against the 19-year-old drinking measure, which is now in limbo and is considered unlikely to come before the full House for consideration.

"We passed the other bill and that will have a far more favorable effect," Kountz said after the vote.

His defection immediately provoked the wrath of Anne Arundel County Sen. H. Erle Schafer, who, according to Kountz, immediately threatened to kill all of Kountz's bills when they reached the Senate floor, to punish him. k

Schafer last night denied he had made such a threat, although he said, "I am annoyed that he changed his vote. I am very annoyed . . . he did a disservice to the citizens of Maryland."

The legislation approved by the Judiciary Committee today sets out a long series of requirements and options for District Court judges who find that youths under 18 have violated the liquor laws, including:

Automatic suspension of violators' driving licenses for at least 30 but not more than 90 days, beginning on the date of the conviction.

For those teen-agers who have no driving license but quality for one in the future, an automatic delay of at least a month in the issuance of the license. This provision, however, lapses if the youth turns 19 before he applies for a driver's license.

In addition to the automatic penalties, judges may also require counseling for the youth or his parents, or both; payment of a $25 fine for a first offense and any subsequent offenses occuringing within a single year, and participation of up to 40 hours in a supervised work program.