The crescendo of rumblings from the right about President Reagan continued yesterday as a small but feisty conservative think tank held a state of the union seminar that judged him to have strayed ominously from his fold.

The attack came from supply-siders, neo-conservatives and gold standard bugs associated with the four-year-old National Center for Legislative Research.

They said the president's economic policies were in "riotous retreat" and his foreign policy was characterized by a pattern of capitulation to the Soviet Union.

The seminar follows hard upon assertions this week by new right direct mail fund-raiser Richard A. Viguerie and other conservatives that their cause would be better served if Reagan does not seek reelection next year.

About 20 New Right political activists had scheduled a meeting in Dallas this weekend to discuss alternatives to Reagan in 1984, but it was called off yesterday because the publicity had transformed it into an unwanted "media event," according to Clymer Wright, Reagan's 1980 Texas financial manager, who was to have hosted it.

The seminar participants showed no such reticence.

Norman Ture, a supply-side economist who resigned as undersecretary of the treasury last year, called on the administration to "quit its guilt trip on the state of the economy" and to reject "as stridently as it possibly can the idea that the deficits are the cause of the recession."

Misplaced concern over the size of the deficits, he said, had caused the administration to abandon its resolve to cut spending and taxes. "The deficits aren't the mischief makers," he said. " . . . History shows they have no relation to interest rates, inflation or capital formation. The Economic Recovery Tax Act of 1981 was just a first step," Ture said, "and we have been in riotous retreat ever since."

Rep. Newt Gingrich (R-Ga.) said he believed the conservative movement is in a tactically more difficult position today than in 1980 because "people think they have taken our medicine and it has failed."

In fact, he argued, the real medicine has not been administered--Reagan merely cut the rate of growth of spending, and he has tempered those modest gains by "throwing money" at the Pentagon.

Think tank founder Paul Dietrich sounded the same theme.

"The press would have you believe that Reaganomics and supply-side economics are synonymous and that they have both been unsuccessful," he said. "This simply is not true."

On foreign policy, Norman Podhoretz, editor of Commentary magazine, faulted the administration for "capitulating" to the anti-nuclear movement in western Europe and the United States by negotiating a reduction in intermediate-range nuclear weapons in Geneva.

"Arms negotiations with the Soviet Union is a lie and a fraud and a deceit to the nation," he said. "Paradoxically, this is what . . . Reagan believes, or used to believe until a year ago."

Meanwhile, the Associated Press reported that U.N. Ambassador Jeane J. Kirkpatrick told the center's Congressional Policy Institute that the United States should consider suspending aid to countries that consistently oppose U.S. interests in the United Nations "unless there is some . . . overriding national . . . or humanitarian interest" not to do so.