Cosatu will march against rape on Friday, said its general secretary Zwelinzima Vavi.
"We need to do far more to combat the shocking level of rape, assault and murder of women and children," Vavi said on Thursday.
He said the rape and murder of 17-year-old Anene Booysen in Bredasdorp, had turned the spotlight on a much wider and deeper problem.
"We read almost daily of rapes and assaults on infants and 97-year-old grannies, and women and children of all ages."
Vavi said the Congress of SA Trade Unions (Cosatu) central executive committee (CEC) had resolved to organise marches on 8 March, International Women's Day, and to picket at the courts where people accused of crimes such as this were appearing.
There would be marches in the North West and the Free State on Friday.
Vavi said the CEC had also resolved to demand the transformation of the whole judicial system.
He said the bail hearing of murder-accused paralympian Oscar Pistorius had shown the world that South Africa's legal system catered only for the rich.
"If you can hire advocates who charge thousands of rand an hour and put up R1-million rand for bail you can soon be back at home."
He said Cosatu would campaign to ensure the poor had access to the justice system.
"The current amounts demanded by lawyers and advocates are way above the heads of workers and the poor. This lies behind deepening levels of inaccessibility of justice to millions."
He said justice was a basic constitutional right, and should not be a privilege for only the wealthy.