A group of Ugandan women stripped to their bras to protest against the alleged sexual assault by police officers of a prominent opposition figure.

The activists made their semi-naked protest after allegations surfaced of the sexual assault of Ingrid Turinawe, a leading female opposition politician.

The women carried placards that read "How would you feel if we squeezed your balls" to the central police station in the capital city of Kampala, the Ugandan Daily Monitor reported.

In a defiant move, several protesters removed their tops outside Kampala's police headquarters, stripping down to their bras.

They were arrested and held for two hours but released without charge.

"We wanted to make the point that we wouldn't tolerate this behaviour," Barbara Allimadi told AFP. "We wanted to ask the police if they are there to do their jobs or there to pinch breasts."

Turinawe is head of the women's league of the opposition Forum for Democratic Change (FDC), led by Kizza Besigye.

The assault happened as police blocked an opposition rally in Nansana on the outskirts of Kampala.

Ugandan TV showed footage of a male police officer repeatedly squeezing Turinawe's breast as other officers attempted to arrest her.

She was taken to a police station and released after the city's lord mayor intervened. She told the press that her breasts were bleeding as a result of the attack and she was in a lot of pain.

Reports suggested that deputy police chief Andrew Kaweesa had and promised an investigation.

Turinawe was the leader of the Activists for Change (A4C), a non-profit organisation that led the Walk to Work campaign in Uganda in April 2011, in protest at rising food prices and deteriorating healthcare.

The movement was repressed by security forces with the deaths of at least four people and more than 100 injured.

The group was banned but its leaders rebranded the movement For God and my Country (4GC), taking after Uganda's motto.