This article is more than 6 years old

This article is more than 6 years old

A group of women in the Japanese capital are threatening a 'sex boycott' against any man who votes for Yoichi Masuzoe in this weekend's gubernatorial election, in protest at the front-runner's claim that menstruation makes women unfit for government.

A Tokyo-based Twitter campaign group – which bills itself as "the association of women who will not have sex with men who vote for Masuzoe" – has garnered almost 3,000 followers since it launched last week.

The founders, who remain anonymous, say in their profile: "We have stood up to prevent Mr Masuzoe, who makes such insulting remarks against women [from being elected] … We won't have sex with men who will vote for Mr Masuzoe."

The 65-year-old former political scientist became a celebrity through TV chatshows before getting involved in politics in 2001. In 1989, he told a men's magazine that it would not be proper to have women at the highest level of government because their menstrual cycle makes them irrational.

"Women are not normal when they are having a period … You can't possibly let them make critical decisions about the country [during their period] such as whether or not to go to war," he said.

Masuzoe has the backing of the conservative ruling party of the prime minister, Shinzo Abe, and is seen as likely to beat his nearest rival, Moriyoshi Hosokawa, a former prime minister who is standing on an anti-nuclear platform, in the elections to become Tokyo governor.

All 16 candidates in the poll are men, with many of them in their 60s or older.

But Masuzoe's comments about women, as well as other controversial remarks on taxing the older people, have resulted in a backlash.

Another website was launched on Wednesday by a group of women also seeking to prevent him from becoming Tokyo governor. The site has attracted 75,000 hits a day and 2,800 people have signed its petition.

"Masuzoe is an enemy of women … He doesn't love Japan. He loves only himself," said one comment on the site, by a woman who identified herself as Etsuko Sato.

On the Twitter campaign feed, a post by manatowar3 said: "I'm an old man. But I cannot tolerate him [Masuzoe] from a man's point of view."

Despite high levels of education, many women in Japan leave career jobs when they have children, and social pressures to be the homemaker remain strong.

There are very few women in senior political positions – Abe's 19-member cabinet has only two – and company boards are overwhelmingly male.

Speaking in Davos, Switzerland, last month, he pledged that 30% of leading positions would be occupied by women by 2020. But most observers suggest this target is unlikely to be met.