One-third of Japanese working women have experienced sexual harassment at their place of employment, although nearly two-thirds of them suffer in silence, a survey has found.

The results of the landmark study commissioned by Japan's Ministry of Health, Labor and Welfare came as Prime Minister Shinzo Abe has pledged to support working women to kick-start the country's struggling economy.

Economists have said for years that Japan needs to make better use of its well-educated but underemployed women, which could go a long way toward plugging the labor gap as the country faces an aging and declining population.

The survey questioned women currently and previously employed, both full and part time, from the ages of 25 to 44 nationwide and received about 10,000 responses. It was conducted in September and October.

About 30 percent in total said they had experienced sexual harassment at work, according to the results, released on Tuesday. Among those employed full time, the figure was slightly higher at about 35 percent.

More than half of those who experienced sexual harassment complained that their appearance, age and physical features were subject to casual comments by male co-workers. Forty percent said they had been touched physically in unpleasant ways.

The survey also found that 38 percent said they were subject to comments or asked questions of a sexual nature. In more serious cases, some said they were asked out relentlessly or were pressed with demands to have sexual relations. But more than 63 percent said they remained silent about the abuse reluctantly, although the survey did not give any reasons for this.

About one in 10 who complained, said they were treated unfairly for speaking up, such as being demoted.

While women are well represented in poorly paid, part-time work, only a fraction of executives at 3,600 listed companies are female.

Japan was ranked 101 out of 145 in the Global Gender Gap Index 2015, released by the World Economic Forum - lower than Suriname and Azerbaijan.