The American public generally supports the development of competition in the telephone business and the pending breakup of the Bell System, despite concerns about maintaining high levels of local telephone service, according to an opinion survey prepared for American Telephone & Telegraph Co.

At the same time, respondents to the March survey were virtually evenly split on whether the nation's telephone system should be revamped. As long as the "telephone system works," 48 percent said it should be "left as it is today," while 49 percent disagreed.

The survey was conducted for AT&T by Lou Harris and Associates and covered issues ranging from the respondents' general view of competition in the telecommunications industry to the January agreement between AT&T and the Justice Department settling the antitrust case against the company. The proposed agreement calls for AT&T to spin off most of its local telephone operations.

According to the survey, the public seems to support the last decade of federal policies which have ended AT&T's complete monopolies in the telephone equipment and long distance businesses.

Overwhelmingly, the survey shows public support for long distance competition, with 82 percent endorsing the requirement in the settlement agreement that local phone companies allow long distance firms to connect to phones on an "equal basis." Only 12 percent opposed that provision.

On the other hand, the public is less certain of the potential value of competition in the equipment fields. Two-thirds of the American public opposes government efforts to force consumers to purchase and maintain their telephone equipment.

Furthermore, 49 percent of those surveyed said it would be a "major inconvenience" to purchase or lease their telephone equipment, while 28 percent said it would be a minor inconvenience and 21 percent said it was "hardly an inconvenience." Under the agreement, local companies will no longer directly provide equipment.

Although 58 percent of the 1,254 adults queried said they had heard of or read about the divestiture agreement and 42 percent had not, two thirds of the group said a federal judge reviewing the agreement should approve it. Fifty-one percent said they favored the agreement, while the proposed pact was opposed by 40 percent.

Eighty percent in the survey felt Congress, currently in the midst of debate over a House bill bitterly opposed by the Bell System, should wait until the agreement has gone into effect before passing telecommunications legislation. The pact is about two years from being implemented.

AT&T suggested that the survey also shows that the public does not seem to favor restrictions on its operations contained in the House legislation. The respondents were read "some of the additional restrictions AT&T's competitors want to place" on the company, and in each case the public opposed the proposals.

By a 50 to 41 margin, the survey showed the public opposed a prohibition on AT&T's offering two-way computerized information services over the telephone network. In addition, the respondents opposed by 54 to 40 requirements that AT&T turn over to the government funds to help maintain local rate levels.

Harris, in a statement, said the poll shows that the American people "are convinced that their telephone service is one of the few things that works well and are fearful" of limits on the Bell System. Harris also said the survey shows the public thinks AT&T and potentially independent operating companies should be "treated equitably with" their competition.