Leaders from Kenya's largest and oldest group dedicated to women's rights, the Women's Development Organization, said they hope the boycott will persuade men to pressure the government to make peace.
Eleven women's groups are participating in the strike. The groups have also called on the wives of President Mwai Kibaki and Prime Minister Raila Odinga to abstain. It was not clear how either wife responded to the request.
"We have looked at all issues which can bring people to talk and we have seen that sex is the answer," said Rukia Subow, chairman of the Women's Development Organization. "It does not know tribe, it does not have a (political) party and it happens in the lowest households."
Sex strikes are rare worldwide. Many men in Kenya are polygamous, as is allowed by law.
Kenyan government spokesman Alfred Mutua said he was unaware of the strike.
The disputed election between Kibaki and then-challenger Odinga led to violence that killed more than 1,000 people and left more than 600,000 homeless. The two were installed after a month of mediation, but infighting has threatened to break apart the fragile coalition.
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