A Japanese magazine has apologised for publishing an article ranking women's universities on how easy it is to convince students to have sex at drinking parties.

The list appeared in the 25 December issue of the weekly magazine Spa! and prompted outrage, particularly online where one woman launched a campaign seeking an apology and suspension of sales of the offending issue.

"2018 was a year where women from all over the world fought for women’s rights, so that our voices were delivered," the petition read.

READ MORE Outrage in Japan as med school admits it cut women's marks

"Japan will be having the first G20 summit this year, 2019 and it is ridiculous for an article such as this to be published. It’s not funny at all."

Her petition on the change.org platform accused the article of "sexualising, objectifying and disrespecting women" and had collected support from more than 28,000 people by Tuesday.

"We would like to apologise for using sensational language to appeal to readers about how they can become intimate with women and for creating a ranking... with real university names... that resulted in a feature that may have offended readers," the magazine's editorial department said in a statement obtained by AFP.

The article was about a practice the magazine described as "gyaranomi" or drinking parties that male participants pay women to attend.

It said the parties are popular among female college students and interviewed the developer of an app intended to help men and women find potential attendees.

The magazine said its list was based on information from its interview with the developer.

"On issues that involve sex, we will do what we can as a magazine to listen to various opinions," the statement said.

There was no indication that the offending issue would be taken off the shelves.

Japan ranks bottom of the G7 countries on female representation in politics and business, and campaigns like the #MeToo movement have struggled to take off in the country.

Last year, a leading medical university admitted it had routinely lowered the scores of female applicants to keep the number of women in the student body at around 30 per cent.

The discovery prompted a probe that uncovered similar discrimination at several other institutions.