South Africans have voted resoundingly to extend the ANC's 20-year rule, ignoring leadership scandals and economic malaise in a wholesale display of loyalty to the party once led by Nelson Mandela.

Final results were expected on Friday, but with about 95% of the ballots counted the ANC had 62.5% of the popular vote, signalling a parliamentary majority big enough to hand President Jacob Zuma a second five-year term.

The party looks set to fall short of the two-thirds majority needed to amend the constitution, and its share of the vote will have fallen for second consecutive election, down from 66% at the last poll, in 2009.

The ANC spokesman Jackson Mthembu said the 102-year-old party – which has held power since helping to end apartheid in 1994 – would receive "an overwhelming mandate" from voters.

The main opposition party, the centrist Democratic Alliance, had 22% of the vote, up from 17% last time, and looked set to top the polls in Johannesburg and Cape Town.

Julius Malema's populist Economic Freedom Fighters had 6.1%, less than a year after the party was formed.

The ANC's status as the party of liberation was drilled home by the recent 20th anniversary of democracy in South Africa and the outpouring of emotion that accompanied Mandela's death in December.

Democratic Alliance and EFF support has been bolstered by a series of scandals surrounding Zuma and frustration at rampant poverty and poor public services.