Contrary to government assertions, income gaps among people in their 30s and 40s widened as much as 30 percent in the 15 years through 2002, a review of official income distribution data showed Sunday.
In January, the Cabinet Office denied there has been a substantial increase in income gaps, arguing that statistical data do not confirm a widening income disparity.
According to studies by a health ministry team led by Yoshihiro Kaneko of the National Institute of Population and Social Security Research, income gaps widened among people aged over 60 in the 15-year period but the gaps were sharply suppressed as a result of redistribution of income, namely pension benefits.
In contrast, no such "redress" via taxation or social security steps was observed among the core active working generations in their 30s and 40s.
The Cabinet Office said widening disparity may be perceived due to increases in elderly households that tend to have sharp income gaps among those who hold jobs and those not working as well as in single-person households with little income.
The office said there have barely been any changes in the "middle-class" awareness among citizens in the past 10 years and those Japanese who believe they are in the middle class are proportionately more than those in the West.
Opposition parties have stepped up claims that gaps between the haves and have-nots have widened after Prime Minister Junichiro Koizumi took office five years ago and pushed for deregulation.