House Majority Leader James C. Wright (D-Tex.), strongly supporting administration plans to hang tough in next week's Geneva talks with the Soviet Union, told a White House meeting yesterday that the two nuclear superpowers should be free to "spend every penny they want" on "Star Wars" and other defensive systems while seeking reductions on offensive nuclear arms.

Wright's strong and unexpected backing for the strategic defensive programs was a much-discussed highlight of a briefing for congressional leaders by President Reagan, Secretary of State George P. Shultz and national security affairs adviser Robert C. McFarlane.

In a telephone interview after he was widely quoted by White House officials and other congressional leaders, Wright said he told Reagan and the others, "I never did understand why we had to start with the ABM anti-ballistic missile treaty. We have no intention of making a first strike against the Soviet Union . So why don't we just tell them you can spend every penny you want on defensive weapons, so long as that can't be a threat? . . . It would be that much less to spend on offensive weapons."

Wright and a White House official quoted Shultz as saying that an unrestricted defensive program, coupled with sharp restrictions on offensive programs, is the "ultimate goal" of the administration. The White House official said Shultz made clear that there is "a negotiations element" in reaching such a dramatically new strategic situation. Today and for the past decade anti-missile defense is sharply limited by the 1972 ABM Treaty, but the few limitations on strategic offensive weapons are relatively ineffective.

Sen. Richard G. Lugar (R-Ind.), incoming chairman of the Senate Foreign Relations Committee, described Reagan as "adamant" that the United States explore strategic defense through the research program he announced in March 1983.

While saying that the administration and congressional leaders are hopeful about next week's Geneva talks, Lugar added, "If there is adamancy on the part of the Soviets it's possible there will be no future meetings for a while" aimed at restarting the suspended arms negotiations between Washington and Moscow.

A number of the congressional leaders expressed caution about public expectations for next week's talks. Senate Majority Leader Robert J. Dole (R-Kans.) quoted Reagan as telling the lawmakers that "we shouldn't be carried away by what might be showing up on the media reports that somehow this is going to be something to end all . . . it's not, it's a preliminary discussion."

Several hours after the congressional briefing, Shultz met privately with Reagan in a session that was expected to produce final instructions before departing late today for his meetings with Soviet Foreign Minister Andrei A. Gromyko. Neither the White House nor the State Department would comment on the Reagan-Shultz session.

Still uncertain is who will accompany the secretary of state into the bargaining sessions with Gromyko and senior Soviet aides. "Shultz keeps emphasizing the table is small," Lugar said after the White House briefing. Lugar said he anticipates that the team is likely to be "Shultz as a negotiator with Mr. Paul Nitze at his right hand and Mr. McFarlane close behind as bearer of the instructions."

A large group of other officials, including some who have often been at odds over arms policies, is to accompany Shultz. But few if any of these are likely to be present at the talks with Gromyko, which are to begin at 10 a.m. Monday (4 a.m. Washington time) at the Soviet mission in the Swiss city.