WASHINGTON (AP) _ Defense Secretary Dick Cheney defended the proposed $7 billion FSX warplane deal with Japan on Wednesday as the Senate Foreign Relations Committee considered a resolution to disapprove the controversial co-production arrangement.

Addressing charges that the deal will give the Japanese vital U.S. technology, Cheney told the committee:

''We are not giving them unrestricted access to all the technology that goes with our capability to design and produce advanced fighter aircraft,''

But Sen. Jesse Helms, R-N.C., the committee's ranking Republican, strongly disagreed.

''The FSX program is a bad deal for America. ... The FSX will be the laboratory and training ground for the design, production, avionics and other engineering talent necessary to build a world-class Japanese civilian aircraft industry.''

The committee originally was scheduled to vote on the FSX issue Wednesday afternoon. But Senate Majority Leader George J. Mitchell, D-Maine, later said the vote had been postponed until Thursday after Sen. Frank H. Murkowski, R- Alaska, requested a closed-door intelligence briefing Thursday morning on reports of involvement by Japanese companies in a weapons complex being built in Libya.

During the hearing, Murkowski said he was ''disturbed'' by the role of Japanese firms in helping to construct the Libyan complex at Rabta, which includes a suspected poison gas plant as well as a metal fabrication plant to produce bomb and shell casings.

Deputy Secretary of State Lawrence S. Eagleburger told the committee there was no evidence that Mitsubishi Heavy Industries, the prime Japanese contractor for the FSX, had any involvement with the Rabta complex.

''Other Japanese companies were involved in the metal fabrication plant, not the chemical plant,'' Eagleburger said.

Even if the resolution passes the House and the Senate, a two-thirds majority in both houses would still be required to override a presidential veto, which would be considered likely.

Under the deal, General Dynamics would join with Mitsubishi to co-develop and co-produce the FSX, an advanced version of the U.S. F-16, for deployment by Japan in the late 1990s. General Dynamics is headquartered in St. Louis, but most of the FSX work would be done at its F-16 plant in Fort Worth, Texas.

Commerce Secretary Robert Mosbacher, who earlier had raised concerns within the administration over economic implications of the FSX deal, told the committee: ''I am confident that this agreement will not harm the economic security interests of the United States.''

Cheney, asked about how solid he views a promise by the Japanese that approximately 40 percent of the production work on the FSX would be handled by U.S. companies, replied, ''We think that it's solid - as solid as it can be.''

Proponents of the FSX deal have argued that it will give the United States valuable ''flowback'' of Japanese technology involving composite wing construction and phased-array radars.

But Sen. Alan J. Dixon, D-Ill., said a report by the General Accounting Office, an investigative arm of Congress, has already concluded that these technologies are well known to U.S. aerospace companies.

''The evidence clearly before us is that we're really not getting anything in return,'' Dixon said.

Sen. Alphonse D'Amato, R-N.Y., called the technology flowback argument ''total nonsense and a facade to cover up the shortcomings of this deal.''

Senators speaking in favor of the deal included Sen. Jeff Bingaman, D-N.M., who argued that if the United States scraps the agreement, Japan will build the new fighter completely on its own or in conjunction with a European country.

''There is going to be an FSX,'' Bingaman said. ''I think that if we do not participate we will lose economic benefits and we will lose technological benefits.''

Also backing the deal was Sen. Richard G. Lugar, R-Ind., who said voting against the FSX would amount to acting in a ''fit of pique'' over the U.S.-Japan $55 billion trade deficit and other outstanding economic issues.