Trade unionist-turned-businessman Cyril Ramaphosa was sworn in Saturday as South Africa's president, vowing to create jobs and tackle deep-rooted corruption that has strangled economic growth.

Ramaphosa, who becomes the country's fourth democratically elected president since the end of apartheid, took the presidential oath before a crowd of about 32,000 people in a rugby stadium in the capital, Pretoria.

"Today our nation enters a new era of hope and renewal," said Ramaphosa, 66, who was flanked by foreign leaders including Congolese President Felix Tshisekedi and Chinese Premier Li Keqiang.