Ms Madikizela-Mandela will be honoured with the Category 1 Funeral which entails elements of military ceremonial honours, Mr Ramaphosa said on Tuesday, Xinhua news agency reported.
Such a funeral is declared for persons of extraordinary credentials specifically designated by the President of South Africa, said Cyril Ramaphosa.
Ms Madikizela-Mandela "deserves the highest respect our nation can demonstrate in honour of a patriot and citizen who served our nation and humanity at large with distinction during our liberation struggle and throughout our democratic dispensation," Ramaphosa said.
In line with this declaration, the National Flag shall, with immediate effect, fly at half-mast at all flag stations countrywide and at South African diplomatic missions abroad, the president said.
This will be observed until the evening of April 14, 2018.
The President further declared national days of mourning from April 3 until April 14.
Further details will be announced as arrangements are finalized in consultation between the government and the family of Ms Madikizela-Mandela, Mr Ramaphosa said.
Winnie Madikizela-Mandela, former President Nelson Mandela's wife, passed away on Monday at a private hospital in Johannesburg after a long illness.
As one of the greatest icons of the struggle against apartheid, Ms Madikizela-Mandela fought fearlessly against the apartheid state and sacrificed her life for the freedom of the country. Her activism and resistance to apartheid landed her in jail on numerous occasions.
After the end of apartheid in 1994, Winnie Madikizela-Mandela served as the Deputy Minister of Arts, Culture, Science and Technology and as a Member of Parliament. She was also the former president of the African National Congress Women's League.