A group of South African women are fighting to overturn a ban on them singing at community events.
They released a protest video on Friday to coincide with Freedom Day, which commemorates South Africa's first post-apartheid elections in 1994.
They say women used to sing at events to mark such events as Israel Independence Day or Holocaust Memorial Day until they were stopped in Johannesburg three years ago.
In Jewish law, there is a prohibition against a man hearing a woman sing, known as kol ishah, although Orthodox rabbis differ in how they apply it.
Campaigner Charlotte Fischer of the South African Centre for Religious Equality and Diversity, said: "Some are free to choose to interpret Jewish law to mean that they should not hear women sing. They do not, however, have the right to impose such restrictions on the broader community.
"There have been two bans. One was by the South African Board of Deputies which organise the Yom HaShoah commemorations. The other was by the Johannesburg branch of the South African Zionist Federation for its Yom Ha'atzmaut celebrations. This year, a group of amazing Israeli women, some of whom you can see in the video, met the SAZF after they tried to allow only half of a mixed choir to perform. The result was a compromise – the mixed choir was allowed to perform this year."
David Sacks, associate director of the South African Board of Deputies, said it had not been the policy to allow women to sing at the event for as long as he could recall.
"It would alienate the strictly Orthodox, they wouldn't come," he said. "There was an incident in 2005 when a teenage schoolgirl sang at the ceremony and the Chief Rabbi walked out."
One Israeli woman in the video says: "I fought for my country so why should I not be allowed to sing my national anthem on stage?"
Protesters say men who object should be told when women are going to sing and given seats that allow them to leave easily.