The ratio of nonregular workers in the labor force in 2011 hit a record average high of 35.2 percent, excluding the three prefectures severely affected by the March quake and tsunami, up 0.8 point from 2010, according to data compiled by the Internal Affairs and Communications Ministry.
The average for the year hit a record for the second straight year, the ministry said Monday.
The rise appears to have stemmed from the growing tendency of firms to hire fewer young people as regular workers and rehire veteran workers on a contract basis after their retirement.
The number of nonregular workers in 44 prefectures totaled 17.3 million, up 480,000 from 2010, it said.
By age bracket, the ratio of nonregular workers came to a record 32.6 percent among people aged between 15 and 34, while that among workers aged 55 and over was 51.5 percent, also an all-time high, the ministry said.
Nonregular workers aged between 15 and 34 numbered 1.7 million, up 20,000, it said.
"What is problematic is that the entrance through which young people are hired as regular workers is narrowing, as seen in the fact that the ratio of college graduates getting jobs has been dwindling," a ministry official said.