Statistics Korea says the number of irregular workers in South Korea reached a six-year high of more than six-point-six million in August.

They now account for 33 percent of the country's 20 million salaried employees.

Their average monthly salary was one-point-64 million won, up four-point-eight percent from a year earlier, but significantly lower than the three million won average for regular workers.

Statistics Korea says there are an additional 36-thousand non-regular, part-time and outsourced workers compared to a year ago.

The number of regular workers grew more slowly, by only three thousand.

About 47 percent of South Korea's non-regular workers are in their 50s and 60s, and more than half of non-regular workers are women.