Passage of a two-to-three-cent-a-gallon increase in Virginia's statewide gasoline tax appeared to be all but a certainty today after the chairman of the House Finance Committee privately indicated he is ready to drop his opposition to the measure.

Del. Archibald A. Campbell (d-Wythe) who has kept Gov. John N. Dalton's proposed four-cent-a-gallon increase bottled up in his finance committee, sent word to the governor today that he is willing to compromise.

Legislators said later that Campbell's action means that the House of Delegates is likely to approve a two-cent-a-gallon increase and that the state Senate is likely to endorse a three-cent-a-gallon increase. That would put the issue before a joint House-Senate conference committee that would be asked to resolve the issue before the end of the control legislative session on March 8.

The statewide tax conceivably could be added on top of a regional 4 percent gasoline sales tax that the House previously has approved for Northern Virginia alone. That measure, intended to pay rising Metro transit costs, would by itself add almost five cents to the retail price of gasoline in the Washington suburbs.

If both taxes win final legislative approval, the price of a gallon of gasoline there could climb as much as eight cents, almost equaling the current nine-cents-a-gallon state gasoline tax.

Legislators cautioned today that the precise impact of Campbell's sudden change on proposals for Metro funding was not known.Dalton, who made the gasoline tax increase his key legislative issue this year, had proposed using the tax revenues for both Metro and highway construction. Although his initial gasoline proposal was quickly defeated, the governor has been attempting to rally support behind the measure, arguing that the state's roads will fall into disrepair if the General Assembly kills the tax increase.

House members said today they believe that the two-cent-per-gallon measure that Campbell's committee is expected to approve specifically will exclude funding for Metro, an issue that is not popular with many down state lawmakers.

Those same supporters say that the Senate is likely to reject the Northern Virginia regional tax and to approve a three-cent-per-gallon statewide tax that would include funding for Metro construction. According to that scenario, the fate of Metro funds would have to be decided in that 11th-hour conference meeting.

In an unrelated action, Campbell's finance committee all but killed hopes for repeal of Virginia's 4 percent sales tax on food by voting down a repeal bill and a compromise measure that would have replaced lost food tax revenues with a one percent increase in the general sales tax.

After an acrimonious hour-long debate, the committee voted down Del. Warren G. Stambaugh's (D-Arlington) bill to repeal the fund tax, 13 to 7.

Stambaugh and Campbell then proposed a substitute measure repealing the tax but replacing lost revenues with a general sales tax boost.

That caused a heated debate with the Northern Virginia delegation, with Fairfax Del. Martin H. Perper (R-Fairfax), a cosponsor of the original repeal bill, leading the opposition. Perper charged that the compromise version would actually mean a tax increase for Northern Virginians, who spent less of their incomes proportionately on food and more on other items than other parts of the state.

The compromise bill failed, 11 to 8, with Stambaugh its only Northern Virginia supporter. A motion to carry the food tax repeal bill over to next year's session -- in effect finishing it off for 1980 -- was put off until Friday.

That was little comfort to Stambaugh. "As far as I'm concerned it's dead," he said after the meeting, adding he would not try for another committee vote.

Campbell, a Southwest Virginia legislator who previously was adamantly against any gasoline tax increase, has told the tax bill's sponsor, Del. Vincent F. Callahan (R-Fairfax), that he thought a compromise was possible.

"He qualified it by saying maybe, and he didn't say how much he'd support," said Callahan, who plans to meet with the finance chairman Thursday morning. Campbell was not available for comment.

Campbell's reversal would remove the last major obstacle to House passage of a two-cent increase. Dalton and his supporters long have said they had support of all major legislative leaders except Campbell for some form of increase. Earlier this week, Dalton said he would be willing to accept a two-cent bill from the House, with hopes the less hostile state Senate would pass at least a three-cent increase.

In the past, Campbell has said he distrusted revenue estimates from the state Highway Department, which would use the new tax money for construction and maintenance of roads. He also had argued the Dalton proposal did not include a proportionate increase in taxes on big trucks, which he says cause an inordinate amount of road damage.

Campbell told Callahan today he was ready to accept Dalton's contention that highway costs had outpaced gasoline tax revenues to the point where some increase was necessary.