Northern Virginia developers and corporations have helped to swell campaign finance totals to more than $5 million in the 1985 Virginia governor's race -- making it the most expensive election in state history.

Unprecedented contributions from the Washington suburbs will push the campaign totals received by Republican Wyatt B. Durrette and Democrat Gerald L. Baliles to almost $7 million by Election Day, officials in both campaigns say.

Almost one-fourth of the $2.7 million Baliles has raised has come from Northern Virginia, while the Durrette camp said it has received a "large chunk" of its $2.6 million from suburban Washington, which the Republican, a former Fairfax County legislator, claims as his base.

Some officials say the trend in contributions represents a sharp turnaround from past campaigns, when a small group of Richmond "Main Street" businessmen and Southwestern Virginia coal companies tended to dominate campaign giving in state elections. Several Northern Virginia political activists say it is a clear sign that the region is attempting to have a more powerful voice in state politics.

"The area is being worked harder than ever before," said Fairfax County Supervisor Thomas M. Davis III, a Republican who has helped coordinate the Durrette campaign in the area. "You have a lot of new people giving that have never been hit before. There's a bit of the struggle between the good ol' boys downstate and Northern Virginia as to who's going to be controlling things. We don't want to get outgunned by downstate."

This year's candidates for governor are expected to raise almost $2 million more than the nominees in the 1981 gubernatorial contest between Democrat Charles S. Robb and Republican J. Marshall Coleman. Campaign officials say escalating media costs and the increasing use of television commercials, especially on Washington TV stations, are the primary contributors to the rising costs.

The Democratic candidate for state attorney general, state Del. Mary Sue Terry of Patrick County, already has raised more money than any candidate to seek that office. Of the more than $1 million her campaign has raised, more than half -- $517,545 -- has already been spent on media costs, according to financial reports filed this week.

Terry has raised almost twice as much as her opponent, Del. W. R. (Buster) O'Brien of Virginia Beach. He listed $528,000 in contributions.

The lopsided figures are "a little bit of a concern to us," said Jeff Gregson, O'Brien's campaign manager. "But I don't lay awake at night worrying about it."

In the campaign for lieutenant governor, Republican state Sen. John H. Chichester, an insurance agent from Stafford County, reported $604,700 in contributions compared to the $464,400 raised by his Democratic opponent, state Sen. L. Douglas Wilder, a Richmond lawyer. The reports showed, however, that Chichester has spent almost twice as much as the Wilder campaign, with Chichester's expenses totaling $517,895, and Wilder's at $169,872.

The three Republican candidates have received hefty contributions from the national Republican Party, most of which has been used for television advertising. National, state and local GOP committees funneled more than $500,000 into the three GOP campaigns.

Both Democratic and Republican officials say Northern Virginia and the burgeoning Hampton Roads region have emerged as major sources of new campaign money this year.

Candidates from both parties show substantial contributions from developers, high-technology corporations and defense contractors in Northern Virginia. For example, William A. Hazel, owner of a Fairfax County construction company, gave $58,800 to the three Republican campaigns, records show.

"There are a lot of new companies in Northern Virginia," said Davis. "The economy is booming. There's a big difference in the base that people are able to give than there has been in the past."

"A regional breakdown of contributions shows growing strength in Northern Virginia," the Baliles campaign reported. The Democrat has received $644,574 from Northern Virginia contributors, one-fourth of his total contributions. An additional 24 percent of Baliles' funds came from Richmond, with about 17 percent of the total from Tidewater.

Republicans said they have already raised about $700,000 in contributions from their scheduled appearance Wednesday by President Reagan in Crystal City. About three-fourths of the $1,000-per-plate lunch donations have been raised in Northern Virginia.