A Virginia task force appointed by Gov. Charles S. Robb today recommended a significant tightening in the state's drunk-driving laws, including stiffer penalties for abusers, the use of sobriety checkpoints and raising the beer-drinking age from 19 to 21.

The proposals, which would cost a total of $4.4 million, are likely to stir considerable controversy in the General Assembly and were denounced by some legislators as an assault on civil liberties. After accepting the report, Robb repeated his earlier support for raising the drinking age to 21, but declined to endorse many of its other proposals, saying that he first wanted to consult with legislative leaders.

Some legislators criticized the task force for playing "politics" with the emotionally charged drunk-driving issue, noting that the group's chairman, Del. Mary Sue Terry (D-Patrick), is widely believed to be considering a campaign for state attorney general in 1985.

"Somebody who wants to run for statewide office always needs something to rattle their bones with," said Sen. Peter K. Babalas (D-Norfolk), an opponent of a higher drinking age.

Terry, a Southside lawyer who championed the drunk-driving issue during this year's legislative session, brushed aside questions about her motivations, saying that the report represented a "balanced approach that doesn't go as far as some states and goes farther than others."

She acknowledged, however, that some of the task force's 51 proposals are likely to meet strong resistance, especially the call for raising the beer-drinking age. The legislature rejected such a move this year and compromised instead by raising the age from 18 to 19. Task force vice chairman Sen. Dudley J. Emick Jr. (D-Botetourt) filed a dissent to the report, saying that he does not believe the assembly will support a further increase "at this time."

Under some of the task force's more controversial recommendations:

Magistrates would impound the driver's license of a drunk-driving suspect immediately after an arrest, replacing current procedures where a license isn't surrendered until a person is convicted.

Police officers could demand that suspects take a blood alcohol test and, if the suspect refused, that refusal would be admissible as evidence of guilt in court.

Police officers could make arrests for drunk driving even if they didn't actually witness the offense.

Also, state police would implement a system of sobriety checkpoints--roadblocks--to snare offenders. Penalties would be toughened. Refusal to take a blood or breath test would result in the suspension of a driver's license for up to one year, instead of the current 90 days. Convicted first- and second-time drunk drivers would have to participate in a program of counseling and education for a mandatory one year, instead of a current average of six to eight months. The last recommendation alone was estimated by the task force to cost between $1.9 million and $3.3 million.

The task force justified its proposals as necessary to combat what it called "one of the nation's most serious health and safety problems." At least one key legislator, Del. Theodore Morrison (D-Newport News), responded with incredulity at some of the proposals, calling them a threat to constitutional liberties. "A person accused of murder, rape or robbery would have more due process than driving under the influence," he said.

The task force's recommendations follow more than two years of impassioned lobbying for stricter laws spearheaded by statewide citizen groups such as Mothers Against Drunk Driving (MADD). In 1982, the legislature first began to respond to such calls by approving a modest increase in penalties. That law, combined with increasing public awareness of the issue, "is now beginning to pay some dividends," Robb said today. Statewide convictions for drunk driving more than doubled, going from 11,724 in 1981 to 24,089 in 1982.

Edward Kunec, president of the Northern Virginia chapter of MADD and a member of the task force, said today he was disappointed that Robb did not make a stronger endorsement of the report, adding, "But our governor is a thoughtful person and he approaches things with caution."