Turbines for the Soviet natural gas pipeline to Western Europe were loaded for shipment yesterday in Bremen, West Germany, and U.S. Commerce Secretary Malcolm Baldrige said the Reagan administration will impose sanctions against the manufacturer, AEG-Kanis, when the ship leaves port.

A shipping company spokesman in Bremen said the vessel, the Bremer Horst Bischoff, is scheduled to sail today.

If the sanctions are imposed, West Germany will become the fourth U.S. ally in Western Europe to have one or more of its companies penalized by the administration.

The resulting friction between the United States and France, Britain, Italy and West Germany is expected to be discussed at an unusual closed-door NATO foreign ministers' meeting this weekend in Canada. Secretary of State George P. Shultz discussed the dispute with his four counterparts this week at the United Nations but they made little headway.

The administration imposed the sanctions with the stated aim of penalizing the Soviet Union and forcing a relaxation of martial law in Poland. Under the sanctions, any company that ships equipment for the pipeline using U.S.-originated or -licensed parts is forbidden from receiving U.S.-made items for any of its energy-related business.

Baldrige said yesterday that when the AEG-Kanis turbines are shipped, "we would take the same action to be consistent with other cases."

Europeans have complained sharply over this application of U.S. law within their countries. They have said that if the United States were serious about penalizing the Soviets it also would halt sale of American grain to Moscow.

What the administration hoped would be a united Western stand against Poland and the Soviet Union has turned into a bitter dispute among North Atlantic Treaty Organization allies that some leading European statesmen believe could undermine the alliance.

While there are signs of a desire to diffuse the issue, U.S. and European officials acknowledge that domestic pressures, particularly in Paris and Washington, make it almost impossible for either side to make the first gesture since it would be interpreted by the other as a cave-in.

U.S. officials, when pressed on the subject, will admit that European countries have taken many of the steps Washington would like as part of a longer range trade policy toward the Soviet bloc. But they added that there has to be a public demonstration of cooperation and agreement with the Reagan administration.

An effort by the four European countries to reach a common position to deal with the United States failed several weeks ago and Shultz has been described as surveying them again to see what common ground there might be for talks. This weekend's session in Canada is being widely viewed as the next major forum for exploring the possibility of a major meeting.

Shultz is known to have argued earlier for limiting the scope of the U.S. sanctions, which were subsequently modified.

One major French company, Creusot-Loire, remained under the original orders until early this week when a Commerce Department hearing examiner ruled in favor of the department's request for the less-sweeping measures, but set aside a request on applying them to 13 of the company's subsidiaries. The Commerce Department moved Tuesday to cut back the number of affected subsidiaries from 13 to four in a step Baldrige said was designed to "avoid placing unnecessary burdens on our allies."

Attorneys for Creusot-Loire are fighting the extension of sanctions to any subsidiaries and also have gone into federal court to challenge the right of the government to impose any sanctions at all.