Eight weeks into their labor negotiations, American Telephone & Telegraph Co. and two unions representing nearly 200,000 workers yesterday moved toward resolving troublesome disputes over job security, wages and other issues that could cause a nationwide strike Sunday by long-distance operators and other employes.

AT&T's initial wage offer yesterday of a 5 percent raise spread over three years was labeled "totally inadequate" by Morton Bahr, president of the Communications Workers of America. But Bahr said the company has made "significant movement" toward the key goal of "lifetime employment" that CWA is seeking for employes.

"We have made what we consider a realistic and reasonable proposal," said AT&T spokesman Herb Linnen. He said the company is optimistic about settling a new contract without a strike, but is preparing a strike plan in case there is a nationwide walkout when the three-year contract expires at 12:01 a.m. Sunday.

In case of a strike, AT&T would be able to easily operate its highly automated phone system with managerial personnel, according to industry analysts. But they said the company would be hurt by walkouts at 26 plants that make, install and repair computer equipment and telecommunications switching equipment used by regional telephone companies.

Local phone service or directory assistance would not be affected.

In the first bargaining since the 1984 breakup of AT&T, the CWA and the International Brotherhood of Electrical Workers (IBEW) are seeking employment-security protections, improved retraining to help workers dislocated by new technology, and wage increases in line with AT&T's current profit levels.

But AT&T, citing the new competitive pressures of a deregulated telecommunications system, is stressing the need to cut costs in its long-distance service and in its money-losing new venture into the computer business.

The ATT bargaining, the largest labor negotiations of 1986, is being closely watched on Wall Street and among labor unions because the new contract could affect AT&T's plans for worldwide expansion and could also influence upcoming negotiations with the seven Bell regional companies employing nearly 300,000 union members. Those companies' union contracts expire Aug. 9.

Neither Bahr nor AT&T officials would discuss further details of the negotiation sessions at the Washington Hilton, but sources on both sides said prospects for a settlement appeared to brighten after AT&T yesterday produced its first formal wage offer, eight weeks after negotiations began April 2. Bahr said he was encouraged that AT&T offered a wage increase instead of a "lump-sum" cash bonus that the company earlier suggested, and which CWA opposed.

AT&T has cut 56,000 of its 380,000 jobs since the 1984 divestiture, and the company plans to eliminate thousands more jobs by introducing new technology, by closing American factories and expanding "offshore" production of computers and telephone equipment in Japan, Korea and other countries that have lower wage rates.

"We want job security because we've had people with 15 or 16 years of service get laid off," said Thomas Hickman, an IBEW negotiator. "We would like to be able to tell a 17-year employe, who is next in line to be laid off, that he doesn't have to worry anymore."

AT&T's annual wages range from about $21,300 for operators to $31,700 for skilled technicians. The unions represent operators, clerical workers, and manufacturing employes who build, maintain, and install large telecommunications and switching equipment.