You will soon see them in Northern Virginia subway stations, at supermarkets, drug stores, high school and PTA meetings, church and civic groups and even at large picnics.

Occasionally, they will even make house calls.

They are Virginia's once reclusive voting registrars, and they are launching a new era in voter registration. The voter registration drive is particularly noteworthy because it is occurring in a state with one of the nation's worst voter-registration records and a history of making it difficult for its citizens, especially black citizens, to vote.

Until this year the registrars had few assistants and no volunteer help. They rarely left their offices except for occasional visits to a library or, in some jurisdictions, a high school.

"The registrars expected would-be voters to come to them," says new Fairfax City registrar Phylis Salak.

And according to the Census Bureau, relatively few did. Only 59.2 percent of Virginia's eligible voters are registered, 1982 census figures show, making Virginia 46th among the 50 states in voter registration.

The District of Columbia is even worse, with only 54.8 percent of its eligible voters registered. Maryland, with 65.7 percent registered, does little better than the national average of 64.1 percent, according to Census Bureau figures.

"But everything's changed. We're now going out to find the voters," says Salak.

Backed by Gov. Charles S. Robb and aided by a new state law that, among other things, allows registrars to cross jurisdictional lines to sign up voters, Fairfax City and its larger neighbors, Fairfax and Arlington counties, are among the most innovative in the new statewide voter-registration campaign.

Last week, for the first time in Northern Virginia history, registrars for Fairfax County and Fairfax City set up a table together at the busy state Motor Vehicle Division office at 10342 Lee Highway in the city, a site visited daily by an average of more than 500 county and city residents.

They said they astounded themselves by registering more than 60 new voters, including a number of recent high school graduates who had reached the voting age of 18, and many new residents who had just moved into the city and county and had come to register their cars, not themselves.

But the big surprises among the new sign-ups were the more than half-dozen citizens who had lived here for years--some 10 to 20 years or more--yet had never voted or registered before.

The first to sign up was the assistant director of the Motor Vehicle Division himself, Conrad Stephens, who has lived in Fairfax City since 1979 but never bothered to register.

Stephens said it always was too difficult during working hours to register.

Marian Marin of Annandale, who has not been a registered voter since 1971, also signed up. "I probably still wouldn't be registered if I hadn't seen them here when I came to renew my driver's license." said Marin, a registered nurse.

Arlington County is trying some of the most unusual new voter-attracting techniques, including setting up voter-registration booths in eight of its nine Metro subway stations--excluding only Arlington Cemetery--and also going to supermarkets, drug stores and numerous shopping centers.

Fairfax City registrars plan to start attending back-to-school nights and PTA meetings, apartment complexes and the city health clinic, as well as the Motor Vehicle Division office.

Fairfax County registrar Lilyan Spero said state officials hope to raise voter registration by 10 percent with the new voter-grabbing techniques. But she said she doubted the county could sign up 29,000 new voters this fall, even with extra efforts by her full-time staff of nine and the 150 new volunteer registrars the county is training to help in the voter-registration drive.

Virginia has had such a poor voter-registration record with minorities that it is required under the Civil Rights Voting Act to publicly announce in newspapers whenever it is holding voter registration sessions.

But area registrars say the Census Bureau's registration figures are based on total population and do not account for Northern Virginia's large number of foreign citizens who cannot vote here and military residents who may keep legal addresses in other states.

Falls Church registrar Sarita Hammer has gotten permission to set up a booth this fall in the city's only enclosed shopping mall. She estimates that about 51 percent of eligible voters in her wealthy small city of 9,000 are registered and that sometimes only 12 percent of them turn out in elections.

"So how many registered voters you have doesn't make much difference if they don't come out and vote," Hammer said.

Virginia is one of the few states with computerized "and really accurate voting lists," according to Fairfax City registrar Salak. This, she said, is partly because the state once used Social Security numbers to identify state voters (and motorists) before federal law prohibited use of Social Security numbers to identify citizens.

Gov. Robb's press spokesman, George Stoddart, says Virginia has "certainly had a history of keeping the electorate small and manageable . . . but the governor and the legislature are committed" to changing that.

Most Northern Virginia registrars "are now doing things that have never been done before," says Salak. "We're really almost making house calls. . . . I'm going to some apartment complexes Sept. 2 which is rent pay day and when most people move."