According to Maimane, only one minister, Rob Davis, officially met with the controversial family, but since the revelation that finance minister Nhlanhla Nene had met with them several times while deputy finance minister, despite having previously denied this, Maimane wants to grill other ministers under the belief that they too may have met with the Guptas.
Last week, Nene told an inquiry panel about the meetings he had held with the business family, a fact that he had earlier denied. "I should have disclosed early, and fully, the details of these meetings".
Former central bank chief Tito Mboweni will take over from Nene. "I deeply regret these lapses and beg your forgiveness".
Mr. Nene had committed "errors of judgment" but was not personally implicated in any wrongdoing, Mr. Ramaphosa said in his announcement on Tuesday.
Rumours of his intended resignation on Monday led to a fall in the value of South Africa's currency, the rand, but it has since recovered its value.
In February, Mboweni tweeted that he was "not available for Minister of Finance". He remained active in politics, and was elected to the ruling African National Congress's decision-making national executive committee at a party congress in December.
Jeremy Hunt demands answers over missing Saudi journalist Jamal Khashoggi
Meanwhile, Saudi Arabia on October 9 invited Turkish experts and relevant officials to visit its Istanbul consulate. Friends and officials have blamed Riyadh for the dissident journalist's disappearance and alleged murder.
Moody's is set to review its rating on Friday, and Nene's departure risks rattling fragile investor sentiment towards an economy in recession.
It's understood the minister offered to resign during a phone call to the president. The nuclear project was eventually shelved.
Questions have also been raised about a PIC deal involving Nene's son, while he was chairman of the PIC.
Mboweni, who went into exile during apartheid, trained as an economist and served for four years as labor minister in former President Nelson Mandela's cabinet after apartheid ended in 1994.
"Mr Mboweni takes on this responsibility at a critical time for our economy, as we intensify co-operation among all social partners to increase investment, accelerate growth and create jobs on a substantial scale".
Public servants at all spheres and levels of government will have no obligation to responsibly manage state fiscal resources under a compromised minister of finance.