Northern Virginia voters will be confronted by a record number of candidates in primary election contests when they go to the polls June 12 to select Democratic and Republican candidates for numerous local and state egislative races.

There are 67 candidates competing in 20 separate primaries in Alexandria and in Arlington, Fairfax, Loudoun and Prince William counties.

"This is the most extensive primary with the most multiplicity of candidates we've ever seen," said Mel Rappleyea, secretary and administrator of the Fairfax County Board of Elections.

For the first time, the Fairfax Republican Party - considered one of the best organized local political groups in the state - is holding primaries in state senate and board of supervisors races.

There are eight primary contests in the Virginia suburbs for General Assembly races, including four Senate and four House of Delegates nominating contests. Other primary races will determine nominees for sheriff, county prosecutors and county supervisors.

Virginia voters don't register by party, but Rappleyea cautioned primary voters that they will have to ask for either Republican or Democratic ballots when they vote.

"But this doesn't make you a Democrat or a Republican just because you voted in one of those party's primaries," he said.

Voters turnout is considered crucial to the outcome because many voters often bypass these preliminary contests. The primary winner will run in Virginia's Nov. 6 general elections.

The hottest primary contest in the region is undoubtedly that between incumbent state Sen. Charles Waddell and his democratic challenger state Del. Raymond E. Vickery.

Waddell, an airline employe, has represented Loudon County and the western part of Fairfax County since 1972. Vickery, a lawyer, has abandoned a seat to challenge Waddell largely on the issue of who can provide the most effective leadership. The race has split Democrats in the 33rd District into bitter camps.

In the 34th Senate District, former Virginia commonwealth secretary Cynthia Newman is seeking the Republican nomination against John Thoburn, the young son of conservative state Del. Robert Thoburn. The winner of that race in Fairfax City and the central portion of Fairfax County will face longtime incumbent Sen. Adelard L. Brault, the Senate's majority leader, and a Democrat.

Democrats and Republicans are locked in noteworthy primary campaigns in the 35th Senate District, which encompassess southern Fairfax County. There, two-term Del. Richard Saslaw and Jean Packard, former chairman of the Fairfax County Board of Supervisors, both want the Democratic nomination for the seat being vacated by retiring Sen. Omer Hirst.

Republicans are in a four-way race for their senior Northern Virginia state legislator. In that contest, former House delegate and unsuccessful congressional nominee James Tate is considered a front-runner among a field including, William Whalen, Richard Calvert and Robert Murrin.

The primary races in the four House of Delegates contest have drawn numerous Democratic and Republican candidates.

In an election for five spots on the Democratic ticket in the 18th District that includes the northern half of Fairfax and Falls Church, there are seven candidates. Incumbent Dels. Dorothy McDiarmid and Kenneth Plum are seeking re-election along will Gary Eklund, Barbara Weiss, Dean Brundage, Wayne Lynch and Mike Morris.

Five republicans, including incumbents Vincent F. Callahan Jr. and Martin Perper, have already been designated the prty's nominees in the general election. But a sixth candidate who was disqualified is challenging that action and a primary may yet be nescessary.

Democrats and Republicans are both holding primaries in the 19th House District, which encompassess southern Fairfax County, Del. Gladys Keating is the only incumbent in the democratic race, and contestants for five seats on the ticket include Jane King, Beverly Schwarz, David Temple Jr., Charles Kaufman, Lester Fettig and William Randels.

Republicans in the 19th District are fielding nine candidates for the five spots on the ticket. They include three incumbents, Dels. Warren Barry, Robert Harris and Robert Thoburn and Roger Grooms, Belden Bell, Lawrence Pratt, John Adams, M. Lee Minnis and former Del. James Dillard.

Democrats and Republicans in Alexandria had to do some fast scrambling when both parties suddenly lost their incumbents for the city's two seats in the House.

The Republicans are counting on Michael Norris to keep the seat held by Del. Gary Myers, the attorney who ousted former House majority leader James M. Thomson, Myers is quitting the legislature after one term.

Three Democrats, Bernard Cohen, Nancy Bennett and Joseph Guiffre, are in a primary race for the two nominations. The winners in that contest hope to recapture the Myers' seat and hold on to the one being vacated by incumbent Del. Richard Hobson.

In Arlington, the House and Senate Democratic incumbents from the two districts representing that county are unopposed. The same is true for Democratic House incumbents from Loudoun and Prince William counties and for the incumbent Democratic state senator who represents Prince William.

In local goverment races, M. L. Greenquist, M. Wayne Huggins and Howard nomination for sheriff of Fairfax County. The winner will face either Kenneth Wilson or Terry Armstrong, the Democratic candidates.

The Fairfax County Board of Supervisiors contest has Republicians Gwendalyn Cody, E. Stanley Rittenhouse and Thomas Schaaf seeking the party's nomination from the Providence District. Republicans Harry Bedsworth and Marie Travesky are seeking the nomination to represent Springfield.

Democrats Betsy Hinkle and Nancy Shands are seeking the nomination to represent the Mason District on the board, while Charles Coe and Sandra Duckworth are vying for the Mount Vernon District nomination.

In Arlington County, Incumbent Democratic Commonwealth's Attorne William Burroughs Jr. is being challenged vy John Purdy. In Alexandria, Republican candidates Ken Foran and Barry Poretz are vying for the chance to challenge incumbent Commonwealth's Attorney John Kloch, a Democrat.

A sheriff's contest in Manassas pits C. Allen Rollins Jr. against Vincent Tassa Jr., both Democrats. The board of supervisors race in Prince William County Democrats is between Helen Tobey and William Weston for the seat representing the Dumfries district.

In Loudoun County, Henry Stowers and Tavis Sample are seeking election to the Board of Supervisors from the Dulles district. The current commissioner of revenue in the county, Lee Keyes, is being challenged by Reginald Gheen and Fred D'Elia. All are Democratic contests.

The sheriff's race in the county pits the incumbent, Democrat Robert Legard, against challengers Frank Beers, Edward Pifer and James Boyd.