South African President Cyril Ramaphosa vowed on Saturday to do more on issues including jobs and state welfare as he campaigned ahead of elections next week that polls suggest could loosen the African National Congress' 30-year grip on power.

Political parties are holding rallies in the final weekend before the national and provincial elections on May 29, which Ramaphosa called one of the most important in the country's history.

If poll predictions prove accurate, the African National Congress (ANC), which has faced corruption scandals, a sky-high unemployment rate and economic stagnation, could win less than 50 percent of the vote.

Such an outcome would mean it would have to seek one or more coalition partners for the first time since coming to power under the leadership of liberation hero Nelson Mandela at the end of apartheid.

"We gather here carrying with us the hopes and aspirations of millions of our people ... to declare that together, we will do more and we will do better," Ramaphosa told supporters dressed in the ANC's colors of yellow, green and black who gathered at a soccer stadium in the country's most populous township, Soweto.

In comments broadcast on national television, he said the ANC would focus on getting more South Africans into work, tackle the high cost of living, maintain existing social grants and progressively implement a basic income support grant for the unemployed.