The Department of Justice, in its antitrust suit against American Telephone and Telegraph Co., has asked a federal judge to find AT&T in civil contempt of court because the communications giant has delayed as much as a year in producing more than 3.1 million pages in documents.

The request, contained in documents filed with the court, also asks for sanctions against AT&T that could include payment of costs and fees as a result of the request -- a figure the government said could reach $3.5 million.

The contempt motion, the first such sanction sought by the government since the case began in 1974, charges that AT&T -- in violation of a pretrial order issued by U.S. District Judge Harold Greene -- failed to turn over key documents for as long as a year after they were required to have been delivered to the government.

As a result of the problem, the government also asked that its attorneys be given access to AT&T computer records indexing the controversial documents.

"There is simply no way that these documents -- 3.1 million pages -- can be processed, screened, sorted and analyzed by plaintiff in time for use at the trial," the government said in its motion.

In a subsequent filing, the government said its analysis of key documents "has been irretrievably telescoped from one year to a few weeks." It also charged that AT&T's "noncompliance" with Greene's order "may well be even more widespread than the particular instances [cited]."

While testimony continued in the telephone equipment phase of the government antitrust suit, the contempt issue has clearly added to the friction between the two sides.

In AT&T's response to the government charge, which was filed Feb. 10, at a time when the two parties were involved in intense efforts to reach a settlement in the case, AT&T called the contempt request "a strategem chosen to attempt to embarrass the defendants and achieve some other tactical objective at this stage of the litigation.

"Defendants will not attempt to match the government's invective, but defendants do take strong exception to the government's reckless charges," lawyers for AT&T wrote.

AT&T denied that it had violated a pretrial order by Greene, saying they "have made an effort to comply fully with the discovery rules and with the pretrial procedures" set by Greene, and charged that the motion is "simply an ill-considered tactic to obtain access" to AT&T's "data base" and "work product at the eleventh hour of this litigation."

AT&T said it had an understanding that the government did not want all the documents, a position the Bell System said was confirmed when the Justice Department "refused" AT&T's offer of documents produced to them in the MCI Communications Corp. suit against AT&T.

AT&T also claimed in that response that the document problem may have been the result of a "clerical error."

At issue in the government charges is a December 1976 Greene ruling saying that any documents received from outside parties by either the goverment or AT&T must be made "immediately available" to the other side.

The government motion says the documents are from two other antitrust suits against AT&T -- one involving Wyly Corp. and Datra Transmission company and the other involving International Telephone & Telegraph Corp. After the Wyly case was settled, the two companies agreed to a discovery plan on April 21, 1980.

Subsequently, the government said it received 583,747 pages of documents and its lawyers thought they had received all the documents covered by a subpoena. But during stipulation negotiations in the AT&T suit, government lawyers "noticed that defendants were introducing" documents not in the hands of the government.

The government said AT&T did not respond to an Oct. 30, 1980, letter from the Justice Department asking for all missing microfilm documents. After another letter, AT&T produced 13 boxes of microfiche documents on Nov. 20, one month before the trial was to have opened.

"To its surprise and shock, plaintiff discovered that these boxes contained almost two million pages of documents which plaintiff had never seen before," the government said.

The situation with the ITT documents is similar, the government charged. ITT signed an agreement to turn over documents to AT&T on Sept. 6, 1979. Not until Nov. 25, 1980, nearly two years after the government filed a subpoena, were another million pages of documents delivered to the Justice Department, the government charged.

The Justice Department went on to say that if the documents had been delivered on time, their processing would have taken about four months, work that would have cost about $3.5 million. The government said that now it would cost significantly more to do the work.