The income gap between regular and nonregular employees further widened this year amid continuous increase in the number of temporary and part-time jobs, data of the state-run statistical office showed Wednesday.

According to Statistics Korea, the average monthly wage of regular workers came to 2.69 million won ($2,380) as of August, up 92,000 won or 3.5 percent, from a year earlier.

In contrast, the on-year increase of the average wage for nonregular workers stood at 14,000 won or 1 percent growth. They were paid 1.46 million won per month as of August.

As a result, the salary gap between the two categories widened from 1.15 million won to 1.24 million won over the past year. The monthly salary disparity was 990,000 won in 2009.

After the number of nonregular workers topped the record 6 million mark last year, it steadily rose to reach 6.27 million in August, Statistics Korea said.

It also said the share of nonregular employees in the total climbed 0.1 percentage point, or 194,000, to reach 32.5 percent.

By age, people in their 50s took up a majority of the nonregular jobs with 1.34 million, followed by 1.31 million in their 60s, 1.27 million in their 40s and 34 percent in their 30s and 20s.

Workers in their 50s surpassed those in their 40s in the nonregular segment for the first time this year ― at 21.5 percent versus 20.4 percent.

By Kim Yon-se (kys@heraldcorp.com)