Although an estimated 41 percent of nonregular workers are doing work on par with that of regular employees, only 16 percent are getting the same pay, a labor ministry study said Wednesday.

The study also found 36 percent of responding companies were hiring nonregular workers, with 54 percent saying they would be unable to operate without them.

The Health, Labor and Welfare Ministry made the estimates about workers on fixed-term contracts, including part-timers and temporary workers, based on a survey in July of about 6,200 companies.

Of those workers, 41 percent were assigned jobs similar to permanent employees, while 54 were given easier tasks. The survey also found that only 1 percent had contracts based on their area of expertise.

Nonregular workers' remuneration was 60 percent to 80 percent of the base salaries of regular employees for 32 percent of the businesses, and about equal for 16 percent.

The contract periods ranged from six months to a year for 54 percent of the businesses, and three to six months for 20 percent of firms. The duration of actual work periods for nonregular workers were one to three years for 29 percent and three to five years for 28 percent.

As for the reasons for employing nonregular workers, 39 percent of the companies were aiming to adjust their workforce in line with changes in quantity, while 38 percent were attempting to reduce personnel costs. Up to three answers were allowed to this question.

A separate Internet survey of about 5,000 workers on fixed-term contracts, meanwhile, found that 50 percent have either not had their contracts renewed or seen colleagues let go.

Annual incomes ranged from ¥1 million to ¥2 million for 31 percent of nonregular workers, and ¥2 million to ¥3 million for 25 percent of workers.

Some 39 percent of workers replied they chose the work because they could not find regular jobs, while 32 percent said the jobs matched their requirements. Multiple answers were allowed.