The long-troubled Immigration and Naturalization Service continues to be "an agency at odds with itself," difficult to manage, uncertain of its future, and ripe for corruption and fraud, a new investigation has found.

"Over the past decade weak management systems and inconsistent leadership have allowed serious problems to go unresolved," a draft report prepared by the General Accounting Office concluded. "As a result, the agency has degenerated into a group of segmented autonomous programs. . . . "

The 177-page report portrays the Justice Department agency, which is charged with administering the country's immigration laws and guarding its borders, as a bureaucratic quagmire lacking "clearly defined goals, priorities and plans."

Among the report's major findings:

While there are long waits at several major Mexican border crossings, the agency has established 40 Border Patrol stations far from any international boundary. It said these stations have 415 agents and are in places such as Grand Rapids, Mich., Roseburg, Ore., and Dallas.

Personnel procedures were described as so lax that many INS inspectors were said to have grown accustomed to earning an extra $10,000 to $20,000 a year in overtime payments. The payments had become so large that INS executives were reported to be fearful they could not stop the payments without causing serious problems in the inspection staff.

The GAO charged that the overtime payments had become so huge that some inspectors were making more than $78,200 a year -- the congressionally mandated "pay cap" for most federal workers.

Lax accounting procedures at INS offices, which collect $300 million a year in fees, have created "a significant and unnecessary degree of potential for fraud," the GAO said. Officials at a large INS office in Los Angeles were discovered mailing thousands of dollars in cash each day to a Federal Reserve Bank, a violation of what the GAO described as sound business practices.

Attorney General Dick Thornburgh was so alarmed by the report, which was delivered to the Justice Department two weeks ago, that he took the extraordinary step of announcing formation of a "review committee" of senior executives to oversee immediate changes at the agency. "The INS must be better able to respond to its mission in a more efficient manner," said Thornburgh.

The attorney general, who has long been critical of the agency, promised to provide "appropriate resources to ensure that speedy progress is made in implementing the management reforms."

Although the department acknowledged that the GAO report was critical, Thornburgh sought to separate the criticism from INS Commissioner Gene McNary, a Bush administration appointee. The former county executive of St. Louis County, Mo., took charge of the agency in October 1989 with a promise to overhaul its operations.

"Many of the problems at the INS were present before current Commissioner McNary was appointed," said the Justice Department's statement, quoting Thornburgh.

A spokesman for McNary declined to comment directly on the unreleased GAO report. "The GAO report, while being highly critical, is critical of a time past," said INS spokesman Verne Jervis.

He quoted McNary as saying that the report "appears to be addressing problems we have already addressed and are on our way to solving." Jervis said McNary had held several meetings with the GAO about the report and was "pleased with the meetings."

The new report follows a similarly critical Justice Department audit Thornburgh ordered in December 1988 and a searing 1989 memorandum given senior Justice Department officials by a former INS general counsel who charged that the agency was "totally disorganized."

The GAO report gives McNary credit for attempting to resolve some of the INS's longstanding troubles, but charges that he has not moved on other major issues such as developing a clear set of priorities and goals for the agency. McNary's staff resisted the GAO's suggestions for better planning, fearing that "unforeseen events would make any planning system obsolete before it is implemented," the GAO said.

"Without coherent, overall direction and basic management reforms, the organization has been unable to effectively address {its} changing enforcement responsibilities and longstanding service delivery problems," the GAO said. Lacking an overall plan for its future, the GAO said, the INS's component units are left on their own and frequently embark on conflicting and overlapping programs.

The GAO noted the agency's well-publicized inability to quickly resolve the applications of various immigrant groups, and went on to describe other less publicized but serious problems.

Budget problems were described as "chaotic." The GAO said that the agency did not know how much money it had to spend last year. On Sept. 30, 1989, for example, there was a $94 million gap between the funds INS believed it had on hand and the size of funds it reported to the Treasury Department, the GAO said. INS officials have been unable to reconcile the difference.

Many of the agency's long-standing problems were laid out, frequently in cold, bureaucratic language. "Leadership needs to develop a systematic management framework that better integrates INS multiple programs and management," said the section that excoriates the lack of leadership by both senior INS and Justice Department officials.

The report questions the staffing levels at many INS facilities, noting that some detention facilities are so poorly staffed that they are well under their prisoner capacity despite the large growth in people being detained by immigration officials.

McNary won praise for his attempt to centralize control in the agency's Washington headquarters and curb the power of the agency's four regional commissioners. Since the Reagan administration these positions have been held by political appointees, officials the GAO said have proved to be eager to defy Washington with separate, often contradictory policies.

A Western employer who was charged with paperwork violations involving six immigrant workers was fined $1,500 by INS officials in the West, but an employer who faced the same number of violations in the South was able to settle his charges for $100, the GAO noted.

Norman Carlson, the former director of the Bureau of Prisons, another Justice Department agency, was named head of the review committee. He will be assisted by Tony Moscato, deputy assistant attorney general for administration, and Don Wortman, director of federal programs for the National Academy of Public Administration and a former official of the Social Security Administration and the Central Intelligence Agency.