American Telephone & Telegraph Co. said yesterday no further subsidies should be extended to long-distance competitors that have asked the Federal Communications Commission for regulatory relief in the transition to a competitive long-distance marketplace.

"They want the FCC to take a whole number of actions designed to hold AT&T back in order to place them in a more competitive postion," said Edith Herman, a spokeswoman for AT&T.

Four long-distance companies, GTE/Sprint, United States Transmission Systems, US Telecom Inc. and Allnet, have petitioned the FCC "to do everything from declaring a moratorium on AT&T offering attractive calling options to asking the FCC to extend the discount on what they pay for access beyond the timetable set by the court," Herman said.

Currently, competitors of AT&T receive a 55 percent discount for inferior connections to the local telephone companies. Under the so-called equal-access process, which eliminates lengthy codes customers previously dialed to reach long-distance companies, the competitors must begin paying full price for superior line connections. Superior connections for competitors, mandated by the breakup of the Bell System, are being phased in across the country and are to be completed by 1986.

The companies are asking that the discount be extended until whole calling area connections are complete rather than phasing discounts out as individual lines receive equal-access capability, Herman said.

The long-distance competitors recently released a study calling for regulatory relief in the face of sharply increased costs of equal access coupled with having to spend billions to complete long-distance phone networks to compete with AT&T. The study suggested that, without such relief, competition to AT&T could be seriously impaired.

"The petitioners' dire predictions, in any event, are completely refuted by the striking growth of their revenues, customers and network capacity over the last half decade -- as well as the recent bullish statements of their top officers and investment analysts about the future of these companies," the study said.

"Petitioners say they seek to promote competition and to benefit consumers, while in reality they prefer to favor particular competitors by imposing on consumers the gratuitous costs of their proposed subsidies and by postponing the consumer benefits of full competition as long as they can," it said.