Conflicts among U.S. policy-makers have stalled the relaxation of export rules on supercomputers, despite an easing of controls on personal and business computers expected to be announced in Paris this week, according to government and industry sources.

New export regulations for supercomputers, advocated by the Department of Commerce, have been stymied by the U.S. Arms Control and Disarmament Agency, an independent entity within the State Department, according to officials who asked not to be named."They've been stirring up the pot," said one Washington lobbyist.

In February, Commerce officials said they hoped to announce a new supercomputer policy in time for the high-level meeting of the 17-nation Coordinating Committee for Multilateral Export Controls in Paris today, though the issue is not on Cocom's agenda.

In January, Commerce said officially that it expected implementation of a new supercomputer rule "in the spring of 1990."

But Washington sources said Monday that resolution of the issue has been delayed, confirming what some government officials have been hinting for months.

One Commerce official said formal interagency meetings may begin sometime in the next two weeks, and a State Department official, requesting anonymity, said earlier meetings have been "desultory," with little basis for further talks until recently.

"In general, supercomputers raise proliferation concerns," said Matt Murphy, a public affairs officer for the arms control agency, although he declined to discuss the agency's stand on Commerce Department proposals.

The fear is that liberalized controls on the most powerful classes of computers could aid development of nuclear weapons and missiles, even though supercomputers would still be banned for sale to Warsaw Pact nations.

But industry representatives fear that Japan and West Germany will take over the $2 billion worldwide market if the United States fails to update its policy in one of the few fields where it still holds a technological edge.

Commerce Department officials carefully steer clear of the term ''liberalization" in describing efforts to redefine the term ''supercomputer," as required by Congress in 1988.

Industry officials, represented by the American Electronics Association, have also tried to stress that the supercomputer issue is not "one of control versus decontrol," but a matter of fixing capability levels at which computers will be subject to the strictest level of licensing rules and inter- governmental assurances.

The problem is the astonishing pace of technology in development of faster computers, rated in millions of floating-point operations a second, known as MFLOPS. Manufacturers like Cray Research Inc. of Minneapolis now build processors rated at 2,700 MFLOPS, effectively 30 times faster than the original supercomputer, the Cray-1, introduced in 1976. Yet U.S. export controls have remained unchanged.

In 1988, Commerce proposed a new multitiered rule that would define a supercomputer as one with just 100 MFLOPS, requiring Commerce authorization for export. Under the rule, machines capable of 300 MFLOPS would require special security plans for sale to 23 Western allies, with lower limits for other countries.

But Debra Waggoner, the electronic association's manager of trade policy, said such a rule makes little sense in light of recent advances. Even Bulgaria now builds a processor capable of 550 MFLOPS, she said.

The association has proposed a "moving definition" that would be based on a standard equal to 25 percent of the average speed of the two fastest available machines. In February, top Commerce officials indicated support for the association's proposal and predicted speedy agreement after consultation with the State and Defense departments.

Although Defense is believed to have agreed, State Department officials expressed strong doubts this week, opting instead for the earlier Commerce plan.