The number of Americans who developed repetitive motion disorders on the job jumped 28 percent in 1989, accounting for nearly all of the increase in workplace injuries last year, the government says.

About 147,000 repetitive trauma disorders among American workers were reported last year - 32,000 more than in 1988, the Labor Department said Wednesday.Repetitive motion disorders include illnesses such as carpal tunnel syndrome, which causes pain in the wrists and forearms. The disorders often are suffered by workers on assembly lines who repeat the same motions with their arms and hands throughout the day.

The Labor Department said there were 284,000 reported cases of occupational illness and 6.3 million job-related injuries among workers in private industry in 1989. That was 136,000 more than the 241,000 illnesses and 6.2 million injuries in 1988.

Although total injuries and illnesses increased by about 2 percent last year, their rate of occurrence in the labor force - 8.6 per 100 full-time workers - was the same as in 1988. The Bureau of Labor Statistics said the increase in numbers of injuries and illnesses tracked the increase in employment and hours worked proportionately.

The survey found about 3,600 work-related deaths. But the agency cautioned that the estimate is probably understated because its survey was not large enough to accurately track all fatalities.

The AFL-CIO, which represents 14.2 million unionized workers, estimates that 10,000 American workers are killed on the job each year and 70,000 are permanently disabled.

Almost half of the 6.3 million injury cases were serious enough for the injured worker to have work activity restricted or to lose work time.