The first direct showdown for the Reagan administration's controversial pipeline policy could occur Tuesday at the French port of Le Havre, where a Soviet freighter is expected to load equipment made with U.S. technology.

The Soviet freighter Borodin was due to arrive at Le Havre Saturday and is expected to begin loading the equipment as early as Tuesday from a wholly owned French subsidiary of the Dallas-based equipment giant, Dresser Industries Inc.

Administration officials said the French government told the State Department late last week that French officials will, if necessary, invoke emergency powers to "requisition" the equipment from its manufacturer, Dresser France.

The loading would be the first concrete confrontation between the United States and its allies over a policy that has been heatedly debated since the West's economic summit in June.

Last Dec. 29, in response to the imposition of martial law in Poland, President Reagan banned the export of American equipment for the 3,600-mile Yamal pipeline that would carry natural gas from the Soviet Union to Western Europe. On June 18, Reagan broadened the ban against participation in the project to include foreign subsidiaries of U.S. firms and European firms that purchase U.S.-licensed equipment.

France, Great Britain, West Germany and Italy have said they will ignore the U.S. export restrictions, and a number of additional shipments are scheduled to begin later this month, including one by a British firm, John Brown Engineering Ltd., whose major components are supplied by General Electric Co.

The Dresser contract involves a half-dozen intermediate-sized compressors that would operate in conjunction with larger turbine compressors. Reports reaching administration officials during the weekend indicated that the Dresser equipment was "on the dock," one official said.

Administration officials said yesterday that an interdepartmental working group of the National Security Council began last Friday to map out a strategy for legal and administrative actions against Dresser Industries, should the loading occur, as well as stern diplomatic messages to the French government.

The group was chaired by Treasury Secretary Donald T. Regan and was scheduled to forward its option papers today to Reagan and his national security affairs adviser, William P. Clark.

A decision on what action to take could come as early as Tuesday, when the NSC working group reconvenes under Secretary of State George P. Shultz, an administration official said.

"The hope is to go the diplomatic route," said one senior official, who emphasized that the president is adamant about not backing off from the sanctions. At the same time, this official said that no decision has been made on what course to take if the first loading occurs at Le Havre. He ruled out any American attempt to physically interfere with the loading.

The official said that lawyers from the State, Defense, Commerce and Justice departments are still hopeful that Dresser officials can be persuaded to take additional steps to stop the shipment.

Moreover, the official said, the administration is planning to tell the French government through the State Department that Reagan takes the export ban seriously and intends to enforce it.

Another administration official said yesterday that the two specific options thus far studied by the working group are seeking a temporary restraining order in U.S. District Court against the Dresser subsidiary's shipment and taking administrative action against Dresser, perhaps going so far as to cut off its French subsidiary from future equipment supplies.

The official added, however, that Dresser officials already have done most of what a court order would require them to do to stop the shipment. This official said that Dresser's top management in Dallas has already ordered the French-based Dresser executives to stop the shipment. Those executives, in turn, told the freight handling company in an Aug. 11 letter that, " . . . All shipment is forbidden until further instructions are given to you in writing . . . . "

Some officials sympathized with Dresser's position, noting that if the company is successful in stopping the shipment, its French executives face severe penalties. If, on the other hand, the shipment is delivered, the American parent company faces severe sanctions under the U.S. Export Administration Act.

The discussion on options also has revealed a continuing difference of approach between Defense and State officials over how firmly the administration should deal with its principal European allies on the pipeline issue. Such differences played a part in the resignation of secretary of state Alexander M. Haig Jr., who supported a more conciliatory approach than was favored in the Pentagon and by the administration.

Defense Department officials reportedly are recommending taking a hard line with the French as a means of denying important economic and technological aid to the Soviets. At the same time, the State Department is known to be searching for a solution that would allow Reagan to maintain his hard-line position on the pipeline while finding a loophole for the Europeans to make good on contract commitments with the Soviets.

But as one former Commerce Department official, who represents several American suppliers, observed, "It's very hard to do that now, especially while the water cannons keep going off harder and harder in Warsaw."