Income disparities have widened among people in their 20s in Japan and will likely get wider despite Prime Minister Junichiro Koizumi's denial of such a trend, according to an annual government report now under compilation.

The gist of the 2006 white paper on labor and the economy, a copy of which was obtained by Kyodo News, also says that the wage gap between regular and nonregular workers is irregular because nonregular wages do not increase according to age.

Nonregular workers include part-time, temporary and contract workers.

The number of nonregular workers came to 15.9 million in 2005, accounting for 32 percent of the country's workforce.

The annual report, which will be released by the Health, Labor and Welfare Ministry in July or August, focuses on analysis of the diversification of employment formats and workers' livelihood.

The document says wage disparities are also widening among regular workers in their 30s and 40s because of the fast spread of performance-based wage systems at Japanese companies, a departure from the traditional age-based wage system that featured life-long employment.

Spending on children's education has declined for the labor force as a whole and increased for regular workers only, suggesting a widening gap in educational opportunities for children.

The marriage rate for nonregular workers is lower, contributing to an unabated decline of the fertility rate in Japan, the report indicates.

As of 2002, married men accounted for about 41 percent of all male regular workers aged from 20 to 34, compared with about 8 percent for nonregular male workers in the same age bracket.

Nonregular workers have fewer chances to develop their capacities than regular ones, the gist says.

Koizumi, rejecting criticism that his government's reform drive has helped widen economic disparities, says his policy is aimed at creating a society where "losers" are given another chance.