The South African National Defence Force (SANDF) are to be on the streets for at least three months to boost the city's struggling police force under the order authorised by President Cyril Ramaphosa.

The number of soldiers deployed was not revealed.

Ramaphosa told lawmakers the soldiers would support police "to restore law and maintain order in communities that are being terrorised by gangsterism" and tackle "the most extreme incidents of violent crime".

Troops in full combat gear brandishing assault rifles were seen standing beside military personnel carriers at road junctions in the Hanover Park and Manenberg townships of Cape Town.

Local residents in Hanover Park largely welcomed the soldiers, saying criminal gangs had taken control.

"It's like we are living in jail and they are free. We must stand with the army to take our community back," Theresa Jantjies, 45, who suffered head injuries when a bullet was fired through her shack two years ago, told AFP.

"The gangs just shoot how they please," she added.

- Gangland violence -

Nadia Hopley, 36, an unemployed mother of four, said she hoped that the army's presence would make the area safer for children.

"When I first saw the army vans passing by, it was amazing because I saw the children with big smiles on their faces, dancing and singing that the army is here to save them.

"The children can finally play freely without gunshots, I hope. Since the shootings have intensified, the local hospital closes in the evening and medical help is further away."

The army has been used in similar missions in Cape Town before. It was called out this time to respond to a spike in violence in recent months in the sprawling townships of the Cape Flats area, one of the most dangerous places in South Africa.

Cape Town, an international tourist destination with stunning coastal and mountain scenery, has the highest murder rate in the country, according to the latest official crime figures.

Police minister Bheki Cele said murders in the Western Cape province, which includes Cape Town, increased 6.3 percent from 3,729 to 3,963 during the year to April 2019.

Last year, over 20,000 people were murdered in South Africa -- 57 per day -- and Cele has described the country as "close to the war zone".

Many wealthy people live in fortified homes with high walls topped with electrical wires, CCTV monitoring and armed guards.