The administration, seeking to enhance public support for President Reagan's defense buildup and to counter the nuclear freeze movement, is considering stepped-up public disclosure of secret intelligence data on Soviet military capabilities, officials said yesterday.

One example of this is expected to occur Wednesday, when the Pentagon publishes a two-year update on Soviet military power. Officials said other such steps are under study.

In particular, some administration officials said they would like to make public a classified briefing by the Defense Intelligence Agency that has been shown to some members of Congress and is described as "very effective."

"What I would like to do is put that on national television in living color," said one official. However, no formal proposal has yet been made to President Reagan on such a release of intelligence data, officials added.

The talk of declassifying some U.S. intelligence data comes on the eve of a key committee vote in the House on a nuclear freeze resolution and of planned demonstrations on Capitol Hill for and against the freeze.

The president opposes the nuclear freeze on grounds that it would lock the United States into an inferior military position relative to the Soviets.

The idea of declassifying more information also comes at a time of apparent disagreement in the intelligence community about the scope of Soviet defense expansion.

Richard Burt, assistant secretary of state for European affairs, told the House Foreign Affairs Committee yesterday that there is an "analytical debate under way in the intelligence community" about the scope and nature of Soviet military expansion.

But Reagan expressed little doubt in remarks yesterday to a conservative group seeking to build public support for his Pentagon budget.

"The Soviet military buildup has increased without letup for over a decade," Reagan told the National Coalition for Peace Through Strength, according to White House spokesman Larry Speakes.

Insisting on the need for his arms modernization effort, Reagan added, "We know the Soviets would not negotiate seriously unless they see such United States programs like the MX intercontinental ballistics missile and the Pershing intermediate range missile deployment actually under way."

But Reagan did not mean to suggest that an arms control agreement with the Soviets would have to wait until after the Pershing II missile deployment in western Europe begins in December, officials said.

The president was urged by the group to declassify more secret intelligence data to counter the nuclear freeze movement and turn around what polls show to be flagging public support for the president's defense buildup.

"The president is probably the best salesman that I know, but in order to sell something you have to present some facts," said Rep. William L. Dickenson (Ala.), ranking Republican on the House Armed Services Committee. "We feel very strongly that the facts have not been presented, that the American people are denied facts on which to base good judgment." He said, for example, that the administration should declassify materials about the accuracy of Soviet nuclear missiles.

Late yesterday, Reagan met on the defense budget with Senate Majority Leader Howard H. Baker Jr. (R-Tenn.), Senate Budget Committee Chairman Pete V. Domenici (R-N.M.), and Defense Secretary Caspar W. Weinberger. The president is scheduled to meet with Weinberger today to review the revised administration publication, "Soviet Military Power."