The State of the Nation address is an annual mix of political pageantry and policy announcements, but the flagship event was postponed last week as Zuma battled to stay in office.
He was forced to resign on Wednesday after the ruling African National Congress (ANC) party turned against him, and pro-business reformist Ramaphosa was sworn in as president on Thursday.
The fight against corruption, allegations of which dogged Zuma and badly dented investor confidence, are expected to feature prominently in the speech, due to be delivered to parliament in Cape Town at 1700 GMT.
"Issues to do with corruption... are on our radar," Ramaphosa said after being elected by parliament on Thursday.
He vowed to use his address "to outline some of the steps we are going to be taking" against graft.
Arriving at parliament on Friday, Ramaphosa told journalists he was "a little bit excited, expectant, a little apprehensive" ahead of the speech, but said he was looking forward to the evening.
After multiple corruption scandals, economic slowdown and falling popularity among voters, the ANC had threatened to oust Zuma via a no-confidence vote in parliament.
Zuma reluctantly resigned, saying he had received "very unfair" treatment from the ANC.
Among the immediate challenges facing Ramaphosa are a gaping 50-billion-rand ($4.3-billion, 3.44-billion-euro) deficit, the threat of further credit ratings downgrades, and 26.7-percent unemployment.
"Ramaphosa will probably remove many Zuma allies in a cabinet shuffle, but only after the budget speech on 21 February," predicted Eurasia Group analyst Darias Jonker.
"(He) will also go after high-level corruption, particularly the Gupta family and their associates, which include members of the Zuma family.
The Guptas are a migrant Indian business family who formed allegedly improper ties to Zuma. They are accused of receiving hugely favourable government deals and even influencing cabinet appointments.
The COSATU trade union federation, an ANC ally, called on Ramaphosa to slim the executive and crack down on government excess.
"Bling lifestyles of the political elite at the expense of the tax payer must be stopped," it said.
The South African Communist Party (SACP), another ANC partner, said Ramaphosa must prioritise "dismantling of parasitic networks surrounding our state and decisively bringing an end to corporate capture of the state."
Stocks, Currency Strengthen
The transition to Ramaphosa saw benchmark South African stocks scoring their biggest gains since June 2016 while the local rand currency reached its strongest level against the US dollar in three years.
In recent years, the radical opposition Economic Freedom Fighters (EFF) party has disrupted Zuma's annual State of the Nation speech with its lawmakers walking out -- or protesting and then being physically ejected from the chamber.
"Walking out of parliament is part of the acceptable practices (of democracy)," said firebrand EFF leader Julius Malema ahead of the speech. "If we need to, we will do that."
The president's address is accompanied by much pomp and will feature a 21-gun-salute, military band and the traditional analysis of fashion choices as delegates and guests arrive on the red carpet.
Ramaphosa, 65, is a former trade unionist who led talks to end apartheid in the early 1990s and then became a multi-millionaire businessman before returning to politics.
Zuma appointed him as deputy president in 2014.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)