Voter registration in Virginia has soared to a record high this year with 381,000 names added to the rolls since January, state elections officials said yesterday.

Officials said 2,666,458 Virginians are registered to vote in the Nov. 6 general election, compared to 2,285,436 at the start of this year. The deadline to register has passed.

Fairfax County officials said preliminary reports show 367,374 eligible voters now compared to 298,171 in 1980, the last presidential year. Arlington County showed 89,082 voters compared to 83,915 in 1980. Several other Northern Virginia area registrars said their registration figures would not be available for several more days.

Susan Fitz-Hugh, secretary of the State Board of Elections, told a news conference in Richmond that the statewide total represents 69 percent of the approximately 3.8 million eligible residents -- an increase of 10 percent over 1980.

In the 1980 presidential election, she said, there were about 2.3 million Virginians registered, or about 59.8 percent of those eligible.

Fitz-Hugh said the record registration could be partially offset by the state's automatic purge of voters who do not cast ballots within a four-year period. More than 265,000 warning notices were sent out recently to persons who have not voted since 1980.

"Now it is up to people to get out and vote. Registration means nothing if people don't go to the polls," she said.

Despite the increases, a task force, appointed last year by Gov. Charles S. Robb and due to report in December, is expected to recommend major changes in voter registration laws for the state, which traditionally has had one of the lowest registration records in the nation.

Fitz-Hugh said this year's registration effort resulted in the sharpest increase in the number of eligible Virginians registered between any two presidential election years.

Registrars, who noted that registration always rises sharply in a presidential year, attributed the higher increase this year to a variety of factors, including aggressive registration drives by Republican, Democratic and independent political groups and recently enacted changes in Virginia's still largely restrictive voter laws.

Politicians and state officials said it was difficult to tell how the new registrations may affect the contests for president and Congress in Virginia because the state does not identify voters by party.

State Republican Party Chairman Donald G. Huffman of Roanoke indicated that the sharp increase in registration was not tilted toward either party.

"We think we have done as well or better than the Democrats," said Huffman, who earlier this year announced an effort to register 50,000 new voters for Reagan. Party officials recently conceded that they could not be sure that many persons had registered.

Huffman discounted the effect of Jesse L. Jackson's presidential campaign in Virginia and more recent visits to the state.

"We have found, for example, where Jesse Jackson helped we didn't see any great upsurge in registration. You have a lot of hype, a lot of people standing around, but not necessarily registering," Huffman said.

Democratic officials, who say Jackson's surprise showing in presidential caucuses boosted registration in the Tidewater area of Norfolk and Hampton, also could not provide firm figures on how many new voters are expected to vote Democratic.