He said in Setswana culture, a child is not supposed to insult his or her parents.
The headman said anyone who "violates" this rule deserves severe punishment. He said this is why he sentenced the woman to four strokes, which were administered on her back.
Apparently, the woman had gone to the headman to report that her husband was abusing her but she ended up on the receiving end.
He said he had "traditional powers" to flog women.
But the acting Director of Tribal Administration, Porati Loeto, does not agree that Mosarwa has such powers.
Loeto said headmen are not supposed to preside over cases but are only there to mediate. He said they can only discipline children with the consent of their parents.
He added that the law does not subject women to corporal punishment.
Loeto hopes Bakwena tribal administration headquarters in Molepolole would deal with this matter.
An official of Ditshwanelo, the Botswana Centre for Human Rights, Peter Tshukudu, said the headman has erred in law. He said a headman of arbitration has no powers to impose a sentence.
A women's rights activist, Ntombi Setshwaelo, also condemned the headman's decision to flog a woman on her backside.
She said these are some of the issues of concern regarding traditional law, which is not written. "This is why we want things to be standardised," said Setshwaelo.
She said when things are not written, it is not easy to interpret them, adding that there is always confusion. "The guiding principles are not specific," she said.
Setshwaelo said they also want flogging of people to be reviewed.
She said she does not condone any culture that advocates violence against anybody not only women.
Violence, she said, is still violence no matter whom it is meted on. "We can't say we are a peaceful society and then perpetuate violence."
Mmegi could not elicit any comment from Emang Basadi officials who have always been vocal about violence against women.
Another women's rights activist, Onneetse Makhumalo, said corporal punishment is violence whether it is applied on men or women. She said there should be other means of punishing people rather than subjecting them to violence.
