Japanese paper Yomiuri Shimbun says Tokyo Medical University began altering results in 2011 to ensure under 30% of successful applicants would be women.

The private university says it will investigate the discrimination reports.

Users online took aim at the Japanese government over the scandal.

Critics suggested the allegations were ironic given Prime Minister Shinzo Abe's stated commitment to boost female participation in the workforce.

Yomiuri Shimbun, which is the country's biggest daily newspaper, published the report examining student admission numbers on Thursday, sparking the complaints.

It quotes an unnamed source saying officials adopted a "silent understanding" to reduce the number of female entrants over concerns female graduates were not going on to practice medicine in employment.

"Many female students who graduate end up leaving the actual medical practice to give birth and raise children," the source told the newspaper.

In 2010, before the measure was allegedly introduced, female student participation was about 40%.

The university is already under investigation over another allegation of exam tampering

The newspaper reports that after the two-round application process earlier this year, only 30 female applicants were accepted to study, versus 141 men.

The story has had national resonance because female participation in the workforce has become a key issue in Japan in recent years under Shinzo Abe's economic agenda.

Female participation has historically been low, especially in expert professions. Research suggests only 12.4% of legislators, senior officials and managers in Japan are female.

Many users shared their surprise and anger at the university on the popular Yahoo Japan website.

One comment, liked almost 30,000 times, said the allegations went "beyond a matter of outdated mindset".

Another suggested the institution's subsidies should be taken away.

Tokyo Medical University is already under investigation over allegations it bribed Futoshi Sano, a high-ranking figure in the education ministry, by demanding he help the institution access a financial grant in return for adding points to his son's entrance exam score.

Futoshi Sano, who was arrested last month, has reportedly denied the allegations.

Reports suggest the alleged gender discrimination may have been uncovered during that investigation.