WASHINGTON, D.C.--The U.S. Postal Service postponed hearings yesterday in its attempt to cut off the incoming mail service of four Boston area termpaper companies.

Thomas A. Ziebarth, a lawyer for the Consumer Protection office of the Postal Service, said yesterday that the hearings were delayed pending the outcome of the Justice Department's appeal of a court decision. That decision forbade the Postal Service from temporarily impounding the incoming mail of the company.

The Postal Service charges that the companies violate a Federal statute which prohibits firms from obtaining money through the mail by means of false representation.

U.S. District Court Judge Frank J. Murray, in denying the temporary stoppage, ruled on November 13 that it was not a proper application of the statute.

"We're holding up our hearings until the Justice Department files its appeal and the legality of our interpretation of the statute is determined." Ziebarth said.

Both the Postal Service suit and the request for the temporary order were initially field on October 18 against Champion Term Papers. Termpapers Unlimited. Academic Research, and Termpapers Incorporated.

Separate hearings will be held for the individual companies by administrative law judges from the Civil Service Commission after the Justice Department's appeal is decided.

However, Ziebarth said that if the judges agree to the mail stoppage the Postmaster General will issue an order to permanently stop the incoming mail of termpaper companies throughout the U.S.

A Justice Department spokesmen said yesterday that the appeal of Murray's decision will probably he find "within a few weeks." Frederic Kellog, an assistant

The four firms involved in the Postal Service suit are also among nine termpaper companies which were barred from selling their products in Massachusetts by Suffolk Court Judge Harry Kalus on October 26.

"Since the Commonwealth has effectively put the companies out of business, the major implications of the outcome of our suit will be on a national level." Ziebarth said.

He added that the Boston firms were chosen for the suit because the District Attorney's office in Boston was willing to cooperate with the Postal Service.