A Maryland appellate court has upheld the right of a police officer to search an automobile, regardless of whether he has a warrant, if his sense of smell defects what he believes to be the pungent aroma of marijuana.

The opinion issued earlier this week came in response to the appeal of a young hitchhiker who was convicted of possessing marijuana with intent to distribute it even after the drive of the car testified that his passenger had no connection with the contraband substance.

"We have no doubt," a three-judge panel of the Court of Special Appeals ruled, "that knowledge gained from the sense of smell alone may be of such character as to give rise to prrobably cause for a belief that a crime is being committed . . .

When such conditions exist, a war rantless arrest infringes upon no constitutional right," said the opinion rendeied by the state's second highest court.

Luther C.West, the attorney for hitchhiker William H. Ford, said yesterday that "the worst thing about this case is that it holds that a mere passenger may be liable."

But advocates of marijuana decriminalization said the ruling is part of a growing body of cased law permitting such searches based on the sense of smell. The group intends to launch a major legal attack against a sense of similar judicial decisions around the country.

"For several months, we're been looking for an appropriate case to take on to challenge this whole concept," said Keith Stroup, director of the Natonal Organization for the Reform of Marijuana Laws (NORML).

Jerry Goldstein, a San Antonio lawyer on NORML's national legal advisory board, said the organization is included in a similar Mississippi case, during which they expect to raise the argument that smell is "not the best of our senses of perception, it's not very reliable," and therefore should not be the basis for a warrantless search.

In another Maryland case, stemming from an arrest in Howard County, a District Court judge suppressed a similar search of an automobile when the arresting officer, during his testimony, identified the odor of sage as that marijuana.

In the case of Ford, the hitchhiker, the officer's sense of smell was not tested in the courtroom. Instead, the judge and, the appellate court, relied on the training he received in the use, effects and detection of marijuana during his time in the Air Force and at the Anne Arundel County Police Academy.

The police offier, James L. Fitzgerald, did testify, however, that marijuana has a distinct, "very sweet, pungent smell." He said he had twice previously made marijuana arrests, both resulting in convictions, in which he had correctly identified the substance at the scene by smell.

After hearing other testimony disputing Fitzgerald's ability to detect marijuana, Chief Circuit Court Judge James macgill denied a defense motion to suppress the search.

The arrest occurerd about 2:15 a.m. on Dec. 29, 1973, when Fitzerald stopped a yellow Volkswagen for speeding. When the driver, a juvenile, stepped from the car, Fitzgerald testified, the officer smelled marijuana on his clothes and also smelled the same odor coming from the car's interior.

The policeman then placed the driver under arrest, reached into the car and puled a brown bag containing marijuana from "the hump . . . where the stick shift is." After determing the bay's contents. Fitzgerald ordered Ford from the car and arrested him, too.

For, described as a young man of around 19, was sentenced to six months of weekends in jail, according to his lawyer. The disposition of the juvenile driver's case could not be learned yesterday.