U.S. Steel Corp. says it will postpone filing unfair trade complaints against nine countries pending the outcome of a meeting on Friday with President Reagan, Commerce Secretary Malcolm Baldrige and the leaders of other major steelmakers.

In a terse statement, the nation's largest steelmaker said it would postpone the complaints it had previously said it would file yesterday "pending a meeting requested by federal government officials later this week to discuss the international trade issue."

However, a Commerce Department spokeswoman said the steelmakers had asked Baldrige to set up a meeting with the president to air concerns about their problems competing with foreign steelmakers and that the administration did not initiate the meeting.

In addition, the president won't attempt to persuade the steelmakers away from filing their own unfair trade practices complaints, the spokeswoman said, but will listen to anything they have to say. She added that the steelmakers are free to file any complaints they want.

The meeting will consist of a general discussion of the industry's problems and the administration will not present any remedies, the spokeswoman said. Another government source said the steelmakers "just want to see the president and see what his feeling is" on their situation.

The administration has rejected suggestions of providing help for a specific industry and has said that it expects the steelmakers to benefit from general tax and other breaks available to business in general.

However, the administration last month itself initiated antidumping and countervailing duty cases against Belgium, Brazil, South Africa, France and Romania in hopes of preventing cases filed by private companies. At that time, Baldrige said the cases were intended to show the world that the United States is vigorously enforcing its trade laws.

The European Economic Community particularly said it is upset by the government's action calling it a "dangerous course." Baldrige and U.S. Trade Representative William E. Brock said last month that tensions between the United States and Europe are becoming more strained --particularly because of the steel problem--and could result in some sort of retaliation from the Europeans.

U.S. Steel has said it would file its own complaints in five product areas because the Commerce Department's action "wasn't broad enough." Together, their cases would cover about 70 percent of imported steel products.

If U.S. Steel filed massive complaints, the Commerce Department said it might eliminate the trigger price mechanism, a controversial system of monitoring steel import prices to protect the domestic steelmakers. If steel enters the United States at levels below the trigger prices, the government is supposed to automatically initiate an investigation.

The domestic steel industry, however, has complained that the government hasn't been tough enough in its monitoring and that it has had to take it upon itself to stop the imports of alleged unfairly priced steel. U.S. Steel had filed antidumping complaints against seven European countries in March 1980, but withdrew them when the Carter administration agreed to strengthen the trigger price mechanism.

On the other hand, the government has said the steel industry should invest its profits back into steelmaking rather than diversification. For example, U.S. Steel recently made a $6.8 billion bid for Marathon Oil Co. It defended its action, saying U.S. Steel's commitment to steelmaking won't be diminished and that it needs to diversify to make a profit.