In his long career as an activist, businessman and politician, Cyril Ramaphosa, South Africa’s president, has overcome many challenges. But few have been as daunting as those he will face when he sits down in his office in Pretoria on Sunday morning.

The first is to consolidate his own position. Despite his electoral win this month, and Saturday’s spectacular inauguration, the 66-year-old is politically weaker than he looks. The African National Congress is deeply divided. Many opposed Ramaphosa’s successful bid for power at an ANC conference in December 2017. Some believe he is too “pro-business” to take radical measures to redistribute wealth in one of the most unequal countries in the world and too close to South Africa’s business community.

Others dislike – and fear – Ramaphosa for more venal reasons. Although he removed Jacob Zuma from power, he has yet to move decisively against the extensive networks of patronage and graft that became entrenched in the party and many major institutions under Zuma’s rule. The public is already impatient with an apparent failure to hold incompetent or corrupt party officials to account, so Ramaphosa needs to show his mettle soon.

The announcement of a new cabinet, possibly as early as Sunday, will signal whether Ramaphosa feels strong enough to take on the legacy of Zuma’s rule, and work to rebuild the integrity of South Africa’s revenue services, security agencies, public utilities and economy.

Unemployment is officially 27%, though most believe it is much higher. There have been rolling nationwide power cuts and the main nationalised power utility has a debt of $30bn, close to 10% of GDP. Economic growth is minimal and the need to invest in infrastructure acute. Levels of violent crime remain very high. The education and health systems are hugely troubled.

The president has immense charm, intelligence, energy and charisma. Close associates say he is not an ideologue but a pragmatic, careful politician who often outfoxes opponents and competitors. But analysts have already described how the “Ramaphoria” that greeted his power grab 17 months ago rapidly ebbed when it became clear that there would be no sudden improvements.

The controversial deputy president, David Mabuza, has been forced to postpone his swearing-in until cleared of graft allegations. Ramaphosa may seize the moment to sideline him permanently or back away from a confrontation. His moves are being watched carefully by both friends and enemies.

Supporters have told critics to give Ramaphosa time. However, with a new mandate, the president has no more excuses for delay.