Lt. Gov. John N. Dalton announced as a Republican candidate for governor of Virginia today at an elaborate luncheon clearly intended to demonstrate that he is the best hope of the state's conservative voters.

Gov. Mills E. Godwin, a conservative former Democrat turned Republican, introduced Dalton and gave him a warm endorsement as "my candidate." Godwin called on Republicans and conservative Democrats to forget the June 14 Democratic primary and concentrate on electing Dalton in the general election.

Godwin's statement reinforces the efforts being made by Dalton supporters to persuade Republicans and moderate-conservative Democrats to back Dalton instead of aiding former Attorney General Andrew P. Miller in his Democratic gubernatorial primary contest with former Lt. Gov. Henry E. Howell. Miller is generally perceived in the state as a moderate and Howell as a moderate-to-liberal populist.

The Dalton event more nearly resembled a late-campaign fund-raiser than the announcement of a candidacy for an election to be held in exactly eight months.

More than 500 people attended the $25-a-plate luncheon in the main ball-room of the John Marshall Hotel here. The speeches by Godwin and Dalton were broadcast over 60 radio stations in Virginia and heard by radio at 85 "satellite" luncheons throughout the state. About two dozen of the luncheons, most of them in private homes, were held in Northern Virginia.

In addition to Godwin, Dalton supporters at the head table today included former Gov. Linwood Holton, Republican members of the Virginia delegation to Congress, party officials and former Secretary of the Navy John Warner and his new wife, actress Elizabeth Taylor.

Recognition of the movie star touched off long applause as the Warners entered the ballroom about 20 minutes after the luncheon began.

Dalton gave a solidly conservative speech. The longest and loudest ap plause came in response to his promise to veto any legislation approving collective bargaining for public employees in Virginia.

"Collective bargaining would lead to higher taxes and interruptions in vital services," he said.

Dalton called for "controlled growth" of "good, clean, nonpolluting industry" in Virginia, In an unusually specific policy statement for a campaign announcement, he also called on the James River in Portsmouth.

The refinery has been strongly opposed by some conservationists and seafood interests, but Dalton said it is needed to shore up fuel distribution in the state. He also called for using a greater share of Virginia's coal production, much of it now exported, in the state.

Dalton praised Godwin for holding down the growth of government, which he nevertheless said had "expanded dramatically in the last 15 years." He said that as governor he would take a close look at the 9,000 unfilled jobs currently in the state government to "see how many can be eliminated without harming the delivery of essential state services."

He also promised he will not be a governor" who comes out with a grab bag" of programs that the state requires local governments to finance with real estate taxes.

Dalton, 45, from Radford in Western Virginia, was a member of the House of Delegates for seven years and of the state Senate for one year before being elected lieutenant government in 1973.

His family name was made famous in Virginia Republican politics by his adoptive father, Ted Dalton, now a semiretired U.S. District Court judge who in 1953 nearly was elected governor. He lost to Thomas B. Stanley, candidate of the long-dominant Democratic organization fostered by the late Harry F. Byrd Sr.

The elder Dalton attended today, but out of deference to the nonpartisan traditions of the bench, did not sit at the head table.

The younger Dalton is perceived as being more comfortable in Virginia's conservative political establishment than his father, who challenged that establishment with a progressive vision of improved public services and race relations.

Godwin praised the candidate's conservatism in his introduction. "In the past weeks and years," he said, "any casual reader of newspaper could not miss the steady stream of liberal ideas represented by bills in the General Assembly. It represents the need for strong, answering leadership behind the governor's desk."

At another point, he said, "I have no reservations about the course of the future of Virginia if the man in whose name we gather here today succeeds to the governor's office. His course will be predictable just as it will be safe."

Although Godwin appeared unrestrained in his endorsement of Dalton, a few hours later at a news conference he said he will concentrate his efforts this fall on winning voter approval of a proposed, $125-million bond issue. "If I am actively participating in that, I would not be actively participating in partisan political activities at the same time," he said

"The two things should not be meshed together.