South Africans are voting for a new national parliament, 25 years after landmark elections ended white-minority rule.
The African National Congress (ANC) has won every parliamentary vote since 1994, and opinion polls suggest the ruling party will secure another majority on Wednesday.
But, President Cyril Ramaphosa is under intensifying pressure to prevent a further erosion of his party's waning popularity. The ANC has seen its share of the parliamentary vote fall from a high of more than 69% in 2004 to 62% in 2014.
The biggest rivals to the ANC are the Democratic Alliance (DA) — the country's main opposition party — and the Economic Freedom Fighters (EFF), a radical leftist group.
The ballot comes at a time when voters in Africa's most industrialized economy are deeply concerned about several issues impacting their daily lives, with roughly half of the adult population currently living below the poverty line.
What's going to happen?
Almost 50 parties will compete for the support of nearly 27 million eligible voters, with the ANC tipped to secure somewhere between 54% and 61% of the vote.
The DA, a center-right party which holds the Western Cape, is reportedly expected to win as much as 22% of the vote, while the EFF is set to receive around 10%.
"The ANC will win with a slightly reduced majority, but it is the provincial breakdown which could have grand implications over whether Ramaphosa is able to implement economic reform," Indigo Ellis, Africa analyst at Verisk Maplecroft, told CNBC via telephone.
"It could even bring into question the entirety of Ramaphosa's position as president," Ellis said.
The ANC, which spearheaded the struggle for freedom in South Africa, has accrued serious reputational damage by successive corruption scandals in recent years.
Under its previous leader, former President Jacob Zuma who was ousted last year, the ruling party was caught up in a series of scandals involving corruption and gross maladministration.
Zuma denies any wrongdoing.
This election is not about black and white, it is about the 'haves' and the 'have-nots.'Pat Thakereditorial director for the Middle East and Africa at the Economist Intelligence Unit
Ramaphosa, a charismatic former trade union leader who succeeded Zuma as ANC leader, has been trying to make amends by cracking down on corruption and stimulating economic growth.
Analysts told CNBC that if the ANC were to win enough votes this week, the success of Ramaphosa's reform agenda would most likely depend on the size of the party's parliamentary majority.
Who is Ramaphosa?
Once seen as potential heir to Nelson Mandela, Ramaphosa lost out to internal battles within the ANC in the 1990s before going on to make a fortune in business.
The 66-year-old lawyer returned to frontline politics as one of the country's wealthiest politicians in 2014, with a reported net worth of about $450 million.
He was elected as ANC leader in 2017, before replacing Zuma as president in February last year.
"In many ways, Ramaphosa is rekindling the optimism of the 1990s but — and it is a big but — the economic, political and social problems are far greater now," Pat Thaker, editorial director for the Middle East and Africa at the Economist Intelligence Unit, told CNBC via telephone.
Alongside concern over violent crime, income inequality and unemployment, many people in South Africa still lack access to electricity and sanitation. Housing is also a hot button issue in the country, with richer households thought to be nearly 10 times wealthier than poor households.
"This election is not about black and white, it is about the 'haves' and the 'have-nots'," Thaker said.
The gap between the so-called "haves" and "have-nots" in South Africa is massive. High-walled mansions and skyscrapers are a constant reminder of the wealth enjoyed by some, while there are millions of others living in townships and squatter camps.
Ramaphosa "may not be the last chance for South Africa, but maybe he is for the ruling party. I think the next election in 2024 could have a completely new party," Thaker said.
Why does the election matter for global investors?
South Africa is a member of the so-called BRICS block of economies — alongside Brazil, Russia, India and China — and is also a member of the G-20 forum of international governments.
Analysts told CNBC the rainbow nation's forthcoming parliamentary vote would have "symbolic meaning for the rest of the continent" too.
At present, financial markets expect the ANC to win around 60% of the votes, according to Silvia Dall'Angelo, senior economist at Hermes Investment Management. That means an even greater majority would most likely trigger a bullish response among investors.
But, she warned a stronger-than-expected mandate for the ANC could in itself be problematic. That's because a vote share of more than 60% for the ruling party is likely to "feed a sense of complacency," potentially delaying much-needed reforms.
"The biggest risk, in my opinion, is that the result of the election just means more of the same for South Africa. You can see a lot of people are already disenchanted and frustrated," Dall'Angelo said.