Gov.-elect Charles S. Robb of Virginia, whose victory Tuesday was underwritten by the overwhelming support of minorities and women, promises the strongest effort ever to bring blacks and women into key roles in state government.

"I am committed to acting affirmatively," said Robb, adding that there is no question that women and blacks will have a greater voice in management of the state when he takes office Jan. 16 as the first Democrat in the governor's mansion in Richmond in 12 years.

Robb said in an interview Friday that while he is a fiscal conservative he has always thought of himself as progressive on social issues. He pledged that his administration will work to eliminate "any obstacles to full participation" by all segments of Virginia's population.

Robb, interviewed in New York during a two-day state-sponsored industry and tourism promotional trip, said he will "look beyond the traditional sources" from which state officials are selected in an effort to "convince blacks in Virginia that if they are well qualified, there is a role for them in state government." The governor-elect said he has no specific numbers in mind, and that merit will be the ultimate determinant of who is hired.

Virginia's constitution gives the governor exceptional appointive power. According to his transition office, Robb will have about 2,300 jobs to fill in the first six months of his administration.

While Republican Gov. John N. Dalton made a similiar pledge when he took office four years ago, his administration has been beset by charges that its commitment to blacks and women was less than enthusiastic. Those complaints culminated this summer in a dispute over a suggestion by Dalton's personnel director that the state abandon its affirmative action plan -- a position Dalton himself disavowed.

Robb said he expects to be an activist governor. "I'm not talking about being a caretaker governor," he said. "I have real expectations for movement. Not just streamlining state government, not just to make it more efficient, but to make it more effective."

Robb also said he is "very much committed" to the Equal Rights Amendment, which will die next summer unless three more states ratify it. Robb said he is even willing to twist the arms of legislators who are opposed to ERA but who owe loyalty to the new governor, if that would make a difference in the outcome.

But he said he doesn't want to "use up my good will . . . while going down to a crushing defeat." Before he acts, Robb said he will "study the new lineup" in the House of Delegates, where the ERA has been locked in committee for nine years.

Another controversial piece of legislation is the proposal to make Martin Luther King's birthday (Jan. 15) a state holiday. State Sen. L. Douglas Wilder (D-Richmond), who sponsored the measure in the past, said he has not talked to Robb about it. A King holiday bill passed the General Assembly last year but was vetoed by Dalton. Robb said at the time and during the campaign that he would have signed it.

"Far more substantive" than any legislation, Wilder said, is the matter of involving blacks at all echelons of government, not just in high visibility cabinet positions, which he called "just the tip of the iceberg. Power in state government resides at the agency and departmemtal level."

Wilder, the only black in the state Senate, said he will suggest appointments to Robb and remind him "who his friends are." Election day surveys and polls indicate that Robb received overwhelming support from the state's black and women voters.

On issues of particular interest to Northern Virginia, an area that gave the 42-year-old McLean lawyer a sizable plurality, Robb said he is "committed to continue the state's share of capital outlays and administrative costs" needed to complete the full 101-mile Metro rail system.

He also said he wants to see an alignment for the controversial Springfield Bypass included in a state highway master plan "so that subsequent development takes that route into consideration."

Robb doesn't know if he will have a chance to fill the vacancy on the State Highway Commission created by the resignation of William B. Wrench, who failed to disclose his ownership of properties near the route that the highway commission picked for the bypass. Robb said he hasn't talked to Dalton about whether he will fill the vacancy before leaving office. "But if the appointment is mine to make, I'll be ready."

Robb said he also feels an obligation to the state's school teachers, many of whom worked in his campaign. Robb said he will propose adding $116 million to a teacher salary incentive fund, which the state uses to help supplement teachers salaries. One of his campaign promises was to bring teacher salaries in Virginia up to the national average, from 39th place among the 50 states.

Robb said Virginia will "feel tremendous pressure from the Reagan budget cuts," but he remains hopeful that he can fulfill his desire to hold state taxes at their current levels.

Because it takes nearly a year to prepare the state's biennial budget, Robb said the 1982-83 budget that will be presented to the legislature will largely be the Dalton's work.

"I will offer some amendments," Robb said, but his budgetary impact won't be felt until the second half of his term.

Robb will have an advantage denied to any recent Virginia governor: The lieutenant governor, attorney general and majorities of both houses in the legislature all are members of his own party. He said he will ask Lt. Gov-elect Richard J. Davis to act as his chief of staff, although Davis may be unable to accept because his state job is a part-time, $16,000-a-year position. In any event, Davis and Attorney General-elect Gerald L. Baliles will be "integral parts of the executive branch," Robb said.

Getting elected, Robb said, was the easy part. Running for office was merely "a necessary prerequisite. The test isn't getting elected, the test is being governor."

Robb said he didn't make the race "to simply test my electability . . . I want to solve problems, to move Virginia forward. I'm turned on by governing."

Robb insisted that "I have no agenda beyond serving as governor -- I hold the old-fashioned belief that it is the ultimate challenge." But he was quick to point out that other people see him differently.

During two days in New York last week, he said strangers sought his autograph, "saying, 'I'm going to save this until the day that you are. . . fill in the blank."