The D.C. Superior Court is $300,000 short of funds to pay jurors and may be forced to halt all civil jury trials for two months this summer, Chief Judge H. Carl Moultrie I warned yesterday.

Testifying at a congressional hearing, Moultrie also disclosed that 900 court employes may have to work for eight to 10 days without pay in September because not enough money has been appropriated to meet the court payroll for the entire fiscal year.

Although the suspension of jury trials would probably apply primarily to civil cases, some criminal cases could be affected as well, Moultrie said.

Court administrator Larry Polansky said a suspension of jury trials could increase the current backlog of criminal trials in the court.

Defendants often decide to plead guilty on the eve of scheduled jury trails, Polansky said, and the prospect of having those trials delayed would reduce the incentive to enter such pleas.

Jurors are now paid $30 a day. At 12-member jury panel cost $360 daily. About 20 panels sit in Superior Court on a typical day, a court official said.

Polansky said a supplemetal appropriation request recently made by Mayor Marion Barry and approved by the City Council would provide only about half the $650,000 needed to pay full wages to court employes. But the package does not include additional money for jury fees because Barry did not request it.

Stephen J. Pollak, president-elect of the D.C. Bar Association, said the threat of a jury shutdown "is very distressing. . . I would think it would be a matter of grave concern to the entire community."

The supplemental seeking an additional $62 million federal payment for citywide programs, will be sent soon to the federal Office of Management and Budget with a request that it be submitted to Congress. City Budget Director Gladys W. Mack said there has been no assurance OMB will send it to Congress, especially at a time when the federal government is trying to curtail spending.

Superior Court has not been hit directly by the mayor's recent order to city agencies to trim $26.1 million from this year's budgeted expenses as part of an effort to avert a deficit that could run as high as $172 million. But the court is being required to operate within the $23.6 million appropriation granted by Congress last year.

The level was so inadequate, Moultrie asserted, that it provided the court with at least 25 fewer employes than it needs to operate at a minimum level.

"It is unreasonable to expect the court system to continue to operate year after year with an ever-increasing work load and fewer employes to handle it," Moultrie declared.

"Even necessities were not at times available when needed because of our severely limited budget," Moultrie said in a prepared statement. "Major programs. . . have been hampered by the lack of jurors (because of insufficient funding) and the inability to provide staff overtime for the extended workday that our judges have undertaken. . .Our budget has betrayed us."

When Moultrie appeared yesterday before Rep. Julian C. Dixion (D-Calif.) the subcommittee chairman, the judge was suffering from laryngitis that left him voicless. Polansky, speacking for Moultrie, said the court faces a deficit of about $1 million, primarily in payroll cost.

Chief Judge Theodore R. Newman Jr. of the D.C. Court of Appeals said his panel, like the Superior Court, also suffers serious underfunding.

Corrections Director Delbert C. Jackson, also appearing before Dixon, said a shortage of funds in his department will require layoffs of 225 employes to meet the mayor's austerity program.

It is, Jackson said, "a sad circumstance. . . the impact is disastrous . . . I am very much upset."