The Montgomery County Police Association, which represents about half the county's force, has issued the first open criticism of Police Chief Robert J. diGrazia, after several months of quiet discontent at various levels within the department.

In a news release, the association said DiGrazia has created "a serious morale problem" by complimenting the department's patrol division while making "derogatory statements" about detectives and other nonuniformed officers, and by not promoting the policemen who are first on the promotion list.

"We feel that the police department is and should be one team working together toward a common goal: to serve and protect the citizens of Montgomery County," the statement said.

"We strongly desire," it continued, "that Chief DiGrazia desist in making statements that tend to erode morale and fragment our department."

Sgt. James F. Mahoney, police association president, couldn't be reached for comment on the statement, which said it was approved unanimously. DiGrazia, through a spokesman, declined comment.

In interviews with reporters and during get-acquainted sessions with county-civic groups and organizations DiGrazia has repeatedly emphasized the importance of the patrol officer on the beat.

"They're out there in the trenches, on the front line," he recently told one group. "For most of the public, they are the police department. It's the most important job. Any (police officer) who comes in and puts on (civilian clothes) should give 10 per cent of his salary back to the guy on the street."

DiGrazia, who was police chief in Boston before taking the Montgomery job last November, has said his intention is to build up the morale of the patrol officers and to make the public realize their importance. Such statements clearly have angered other policemen at various levels within the department.

"While we acknowledge (diGrazia's intention) and applaud his support for the patrol function," the association's statement said, "we feel that cutting off one's left hand to prove that you are right-handed is a little extreme."

The group also said in its statement it has lodged a protest with DiGrazia over his decision not to promote to private first class Pvt. Michael D. Silverstone, 28, a patrolman assigned to the Silver Spring district.

Silverstone, a seven-year member of the force, led his district in criminal arrests last year. Early this month, DiGrazia promoted four officers from private to private first class and two from private first class to corporal.

Sources in the department said the decision to not promote Silverstone involved a minor infraction for which he was disciplined several months ago.

The police association's statement called the action "unjustified and without precedence," and said it "endangers the very concept of a promotional listing."

Some of the discontent with DiGrazia according to some of his critics, stems from the fact that his selection to head the force closed off promotion opportunities for several high-level career officers.

Three veteran officers, the head of the juvenile unit, the commander of the Wheaton district, and the deputy commander of the Silver Spring district, are all retiring at the end of this month.

Several police officers also sharply disagreed with DiGrazia's criticism of the promise District police gave Hanafi Muslim leader Hamaas Abdul Khallis that he would be permitted to go free on his personal bond if he surrendered and gave up the 124 hostages held at three locations in Washington earlier this month.

At the time, DiGrazia said the way to deal with hostage situations is to promise anyting, but give nothing.

"What's going to happen if (a hostage situation) goes down here," said one Montgomery County officer. "Our word won't be worth anything to the kidnapers. What (DiGrazia) said wasn't too smart."