Thousands of South African women took to the streets on Thursday to protest at the government’s failure to deal with rising violence against women in the wake of a string of brutal attacks that have shocked the country.

Women from across South African society marched to parliament in Cape Town dressed in black and purple in commemoration of those who lost their lives in August, the most deadly month for violent crimes against women the country has ever seen.

At least 137 sexual offences are committed per day in South Africa, mainly against women, according to official figures. This week the women’s minister, Maite Nkoana-Mashabane, said more than 30 women were killed by their spouses last month.

Protesters are planning a national shutdown of the country on Friday and are calling for a state of emergency to be declared.

Thousands of people, including local celebrities, have taken to social media to express their anger and frustrations at the killings under the hashtags #NotInMyName #AmINext and #SAShutDown.

On Thursday, young and old took to the streets, women wearing chains, a symbol of how the violence has repressed South African women. Many carried placards reading: “Enough is enough”, “My body is not your crime scene” and pleading with the president, Cyril Ramaphosa, to act against the violence perpetrated against women and children.

South African President, Cyril Ramaphosa, addresses protesters outside parliament in Cape Town. Photograph: AP

Activist Lucinda Evans addressed protesters in front of parliament, stating that the fight against gender-based violence was a 365-day process. “As a country we are in a crisis. Violence against women, children and the LGBTIQ+ is a crisis.

“I am addressing the female ministers. When are you going to hold these men accountable who have been failing us for so long?”

“If this government fails to protect us, we, as the women of South Africa, will take them to the constitutional court,” Evans yelled as the crowd cheered.

In an impromptu address to the protesters, Ramaphosa admitted that it was time his government took emergency measures to deal with the scourge of rape and the murder of women. “Enough is enough and we are going to act,” said Ramaphosa, promising to announce later on Thursday a raft of measures.

“Men that kill and rape must stay in jail for life. The law must change that once you have raped and kill you get life, no bail,” Ramaphosa told the angry crowd.

The first of last month’s victims to make national headlines was Saadiqa Newman, a 26-year-old mother-to-be who was shot eight times by gangsters. Denusha Witbooi was then murdered in her vehicle by unknown gunmen, while equestrian rider Meghan Cremer was found murdered, tied up and dumped in a sand mine.

Six-year-old Nathlia Pienaar died after she was struck in the head by a bullet while skipping with a rope just outside her home. Lynette Volschenk was found chopped up in her apartment in a gruesome crime committed by a neighbour, and the South African boxing champion, Leighandre Jegels, was shot dead by her police officer boyfriend.

The last straw for many was when the body of 19-year-old missing University of Cape Town student, Uyinene Mrwetyana, was discovered. She disappeared on 24 August on her way to collect a parcel at the local post office.

A post office employee has confessed in court to raping and beating her to death with a set of scales inside the post office, which is situated next door to a police station.

• This article was amended on 7 September 2019 to correct the spelling of Lynette Volschenk’s first name.