Contrary to initial predictions, the pay gap between regular and nonregular workers widened after the enactment of a law aimed at protecting job security of temporary workers in 2007.

According to analysis released by the private Korea Economic Research Institute on Monday, nonregular workers received 74.5 percent of regular employees’ wages on average in 2005.

But the ratio decreased to 65.5 percent in 2009 when the law was applied to all workplaces before a slight uptick to 67.8 percent last year, which indicates that the law failed to improve low-wage labor conditions for temporary workers.

In addition, the number of regular workers increased 3.3 percent annually from 2005 to 2014. But the number of part-timers, dispatch workers and workers hired by service agencies, all of whom are included in the category of nonregular employees, rose 7.7 percent, 5.7 percent and 3.8 percent, respectively.