Malema also alleged that there was more to the allegations around Nene.
With government debt at already dangerously high levels and the country at risk of losing its sole remaining investment-grade credit rating from Moody's Investors Service, Mboweni will have little option but to stick to the National Treasury's expenditure ceilings and deficit-reduction targets.
"The president is concerned about uncertainty that this has created in the markets", Diko said by phone. "Ideologically and in terms of macroeconomic policy thinking, President Ramaphosa may have appointed the finance minister he always desired in his cabinet".
While the governing ANC has praised Nene's contribution during his tenure.
After leaving the bank in 2009, Mboweni went into business, establishing his own investment company and serving on a number of company boards including as the chairperson of AngloGold Ashanti. He is urging those ministers and other senior officials to follow Mr. Nene's example by volunteering to give testimony at the national inquiry into corruption so that their conduct can be reviewed. "He has also said that it is important that he affirms his commitment on the project of economic recovery and stability and because of that he is still to apply his mind with the issues he has discussed with Minister Nene".More news: Nikki Haley Resigning from Trump Administration
Pressure has been piling on finance minister Nhlanhla Nene to resign, following his disclosure to the state-capture inquiry commission, that he had met the Gupta brothers between 2010 and 2013.
The Guptas, who built a vast business empire in the mining and media industries in South Africa after forging a partnership with the son of former president Jacob Zuma, are now under criminal investigation on corruption allegations. "He will strengthen Ramaphosa's hand in cabinet". Gigaba and Bathabile Dlamini, who head the home affairs and women's affairs portfolios respectively, have been ruled to have perjured themselves in court cases.
Mboweni, the nation's fifth finance chief in less than three years, will have to oversee an economy that's fallen into recession and help Ramaphosa rebuild confidence battered by nearly nine years of mismanagement under former President Jacob Zuma.
This, as EFF leader Julius Malema challenged the president on Monday to accept Nene's resignation.
Ramaphosa stressed that Nene "has not been implicated in any act of wrongdoing himself" and hailed him as a minister who had "defended the cause of proper financial management as well as clean governance". "Foreign investors, after a well-managed political transition, have been disappointed and the links between the Guptas and Nene shows it is hard to erase the past".