Supporters of Sen. Edward M. Kennedy's presidential campaign were rebuffed yesterday in their attempt to gain additional Virginia delegates to the Democratic National Convention next month.

Jerome F. Donovan, a hearing officer for the convention's credentials committee, recommended rejection of all the complaints lodged by Kennedy's Virginia backers.

The Massachusetts senator won only five of the 64 Virginia delegates chosen at state and local political meetings this spring. Protesting what they termed heavy-handed tactics by the Carter camp, Kennedy's supporters later appealed to the credentials committee, seeking six additional Kennedy delegates from Virginia.

But in 25-page opinion made public yesterday, Donovan concluded there was insufficient evidence that Kennedy would have gained additional delegates even if the abuses alleged by Kennedy's supporters had occurred. At one point, the hearing officer said the Kennedy camp's claims rested on "unproven speculation."

Ernest S. Kessler, Kennedy's Virginia campaign manager, said it is likely an appeal will be filed with the credentials committee. The 158-member committee is scheduled to meet July 19 and 20 and may accept reject or modify Donovan's recommendations.

If the crfedentials committee upholds the hearing officier's conclusions, Kessler said. "I think that some kind of compromise could have been worked out."

"the good guys win," said George H. Gilliam, President Carter's Virginia campaign chairman. "It's not any surprise. I thought the challengechallenge by Kennedy's backers was frivolous and wholly without merit."

Gilliam rejected Kessler's suggestion of a compromise, arguing that such a move would be "completely contarary to the will of the people."

Th ecomplaints voiced by Kennedy's Virginia supporters at a lengthy hearing last month centered on rules and procedures used in selecting Virginia's 64 delegates in Richmond and elsewhere. The hearing took place at the Democratic National Committee headquarters in Washington.

In one instance, Kennedy's supporters contended that a local convention chairman in Halifax County improperly denied a participant permission to switch from the Carter caucus to the Kennedy caucus.

Kennedy's backers expressed other objections to procedures followed at mass meetings in Richmond and Chesterfield County. They challenged a formula used for apportioning delegates in Richmond and disputed a recount of delegates in Chesterfield County, a Richmond suburb.

Additional complaints were raised by Kennedy's supporters about procedures at the Virginia State Convention in Richmond in May. They cited, in part, a ruling prohibiting delegeates from switching from one candidate's caucus to another and the failure of the convention chairman to conduct a recount.

Donovan repeatedly said, however that he was "unconvinced" that Kennedy would hve benefited if different procedures had been followed.