It is not clear why Mabuza has been the only one on the list who has decided not to take up his parliamentary seat until his name is cleared.
His spokesperson, Thami Ngwenya, said Mabuza's decision was in line with the party's new approach where it requires those who are accused of corruption to clear their names before taking up positions of responsibility.
"Remember, there is an issue of renewal here and therefore these processes must be followed," said Ngwenya.
ANC sources close to Mabuza claimed he first told party officials he was removing his name from the list but they advised him to merely postpone his swearing in until he has had a chance to speak to the integrity commission.
Mabuza's decision has sparked speculation that when Ramaphosa announces his new cabinet on Monday, Mabuza would be replaced either by outgoing higher education minister Naledi Pandor or minister in the presidency Nkosazana Dlamini-Zuma.
It has also raised questions whether a new power struggle has begun in the ruling ANC, even before Ramaphosa has taken office under a fresh popular mandate.
Mabuza has become notorious for playing his cards very close to his chest when it comes to political contests. In the run-up to the ANC elective conference in 2017, he was widely seen as part of a faction that wanted Dlamini-Zuma as president while, behind the scenes, he allegedly encouraged his Mpumalanga delegation to back Ramaphosa.