New figures for 1983 show that "every major statistical indicator" of occupational injuries and illnesses is at the "lowest level ever recorded," according to Robert A. Rowland, the assistant labor secretary who heads the Occupational Safety and Health Administration.

Rowland said the Bureau of Labor Statistics report confirms the effectiveness of the Reagan administration's "nonadversary" approach to employers.

But a House Government Operations subcommittee said the data is "unreliable" because OSHA and the BLS have failed to sufficiently monitor work-place health and safety statistics, especially those relating to diseases caused by exposure to hazardous substances.

Citing a "bipartisan failure" in recent administrations to upgrade data-collection on occupational disease, Rep. Barney Frank, (D-Mass.) chairman of the subcommittee on manpower and housing, said the health-reporting system was "fragmented, unreliable, and 70 years behind" the methods used to track communicable disease.

Many physicians fail to recognize the job-related causes of diseases, the report said, and to compound the underreporting, OSHA and the BLS rely on "inaccurate employer records" to compile data. The committee report recommends that occupational disease data-collection be consolidated under the National Institute of Occupational Safety and Health, a division of the Health and Human Services Department. The committee said such a move could help reduce health-care costs if the causes of illnesses are more acccurately pinpointed.

The BLS survey of 280,000 private businesses for 1983 concluded that work-place injuries and illnesses declined to the lowest rate in more than a decade. The bureau said there were 7.6 injuries and illnesses for every 100 full-time workers last year, down from 7.7 percent in 1982. The highest injury rates were in the construction industry -- 14.7 incidents per 100 workers. The lowest rate was for workers in the finance, insurance and real estate industries -- 1.9 incidents per 100 workers.

Work-place fatalities were 3,100 in 1983, down 25 percent from the 4,090 deaths in the previous year and down more than 40 percent from the 5,340 in 1973.

Rowland said that because the BLS reported fewer incidents in which work days were lost because of injury, OSHA would lower the cutoff point used to decide whether to make "walkaround" inspections in various industries. For instance, the rate of lost work days because of work-place injuries was 4.2 per 100 full-time workers in manufacturing in 1983, meaning that only those employers with higher rates will be subject to such inspections. In 1982, the cutoff figure was 4.3.

DISLOCATED WORKER GRANTS . . . The department has awarded $3 million in grants for three "dislocated workers" projects in Pennsylvania, Michigan and Indiana, states that were hit hard by plant closings and layoffs, according to Frank C. Casillas, assistant secretary for employment and training.

Laporte, Ind., will get $1 million to retrain 600 workers who lost their jobs in auto-related industries. Allegheny County, Pa., will receive $1 million to serve 2,125 people laid off by U.S. Steel, while the Michigan State AFL-CIO will receive $1 million for 800 unemployed mine workers who will be retrained for jobs in health, retailing or other service industries.

RESERVISTS' RIGHTS . . . A three-judge federal appeals panel has upheld a back pay award to Michael Chesna who was fired after asking a Massachusetts firm for a schedule change to attend monthly weekend Naval Reserve drills.

Donald E. Shasteen, deputy assistant labor secretary for veteran's affairs, hailed the ruling as a victory for "re-employment rights" of military reservists.