An estimated 5.4 million workers suffered work-related injuries or illnesses in 1984, an 11.7 percent increase over 1983, the Bureau of Labor Statistics said yesterday.

The increase is the largest single-year jump since the creation of the Occupational Safety and Health Administration in 1972.

Labor Secretary William E. Brock said he was "deeply concerned and disturbed" by the sharp increase, which followed four years of decline. Brock said a major cause of the increase was economic recovery, which put 4.2 million more people on the job, but added that the data also point up the need to "reexamine, reevaluate and redouble our efforts" to make sure that OSHA is helping to protect workers' safety and health.

The AFL-CIO, which has been sharply critical of the administration's cuts in safety inspections and enforcement actions, said: "The results of the BLS survey show serious health and safety problems throughout American industry and that these problems are getting worse. The statistics confirm that Reagan administration policies of weak enforcement and deregulation do not protect workers."

The annual report by the BLS said that, among employers in private industry with 11 or more employes, an estimated 3,740 workers were killed, for a rate of 6.4 deaths per 100,000 workers. Workplace deaths increased by more than 600 from 1983, when the fatality rate was 5.6 per 100,000 workers.

The bureau reported increases in injury and illness in 11 of the 12 major industrial sectors. The highest rate was in construction, which recorded 15.5 injuries per 100 workers, while the lowest was the financial sector, the only industry to improve its safety record, with 1.9 incidents per 100 workers.

The nationwide average of 8 injuries or illnesses per 100 workers was up from 7.6 in 1983, although the rate is still far below the toll of 9 to 11 workers per 100 that prevailed in the 1970s.

Brock said the improved economy has brought large numbers of new and inexperienced workers into jobs, and the bureau's studies have shown that more than 40 percent of total accidents occur among first-year workers.

But economic recovery can account for only about half the increase, because the number of incidents rose 11.7 percent while the total hours worked in an expanding economy rose by 6.6 percent over the year, according to the bureau and the nonpartisan Congressional Office of Technology Assessment.

Under the Reagan administration, OSHA has emphasized a "nonadversary" approach to employers to encourage voluntary compliance, while reducing the number of inspectors, inspections, citations and penalties levied against companies.

"Weak enforcement and less expenditure have finally caught up with them" in the increased injury rate, said AFL-CIO health and safety director Margaret Seminario. "It takes several years for these kinds of changes to show up."

Labor Department officials had pointed to the 1980-83 decline in injury and illness as evidence of OSHA's success. But a highly critical study by the Office of Technology Assessment said the recession during that period was the primary cause for the improvement then.

"Now that the injury rate is up again, the Labor Department has rediscovered the connection between business activity and injury rate," said OTA's Karl Kronebusch.