President Cyril Ramaphosa vowed to create more jobs, boost economic growth and address racial inequalities at a rally on Saturday to launch the ruling party's parliamentary election campaign.

The vote, expected in May, will be a test of whether Ramaphosa has been able to reverse a decline in support for the African National Congress (ANC), which has governed since the end of apartheid in 1994 but has seen its majority wane.

Ramaphosa became head of state in February last year after his allies on the ANC's executive forced scandal-plagued Jacob Zuma to resign, fearing that the corruption affairs and economic stagnation that marked his nine years in power could harm the party's chances at this year's election.

"At the centre of our manifesto is a plan to create many more jobs and ensure that all workers can earn a decent living," Ramaphosa told tens of thousands of ANC supporters packed into Durban's Moses Mabhida stadium.

"The most pressing task for our country is to set the economy on a higher path of shared growth and to transform the structure of our economy to provide opportunities for millions of South Africans," he added.

Ramaphosa and other top ANC officials have been touring Zuma's home province of KwaZulu-Natal this week, projecting an image of unity despite deep rifts within the party, where a faction loyal to Zuma retains significant influence.

Some analysts say a resounding victory for the ANC this year could embolden Ramaphosa in his drive to boost investment and tackle corruption. Others believe he will continue to be constrained by his opponents in Africa's oldest national liberation movement.