Highly respected National Treasury director-general Lungisa Fuzile has confirmed his imminent departure from the department.

Fuzile’s contract was due to end in May 2018. However, prior to the axing by President Jacob Zuma of former Finance Minister Pravin Gordhan on March 31, the director-general requested a redetermination of his contract with an exit date of May 15, 2017.

The National Treasury said in a statement on Wednesday that Fuzile had been signalling his desire to leave the National Treasury for some time.

"In the past few days, Fuzile has been focusing on ensuring a smooth hand over to incoming Finance Minister Malusi Gigaba. Whilst Fuzile has indicated his flexibility to stay on for a reasonable amount of time, if needed, he and the Minister are in discussions on how to ensure that a smooth transition and the institutional strength of National Treasury is sustained and reinforced."

Fuzile’s departure comes amid a Business Day report stating that Gigaba had moved across from Home Affairs to the National Treasury with an entourage of more than 16 ministerial staff and advisers.

Fuzile's exit follows the decision by S&P Global Ratings to lower South Africa's sovereign credit rating to a subinvestment grade of BB+, from BBB-, on political and institutional uncertainty. The agency also sustained its “negative outlook” on the country.

The downgrade was in direct response to Zuma’s Cabinet reshuffle, which “have put at risk fiscal and growth outcomes”.

Moody’s has also initiated a review for downgrade, while Fitch Ratings is expected to make its ratings determination soon.

In the statement confirming his intention the leave the National Treasury, Fuzile said his departure, and that of his previous principals, "should not necessarily lead to a change of course as the mandate of National Treasury is reinforced by the Constitution and a number of other legislations".

"National Treasury officials are competent, highly skilled professionals who are very conscious of their higher duty. Their commitment and diligence is not attached to a Minister, and they will continue to serve the nation to ensure protection of the fiscus and the sound financial management in South Africa under the current leadership of Minister Gigaba and Deputy Minister Sfiso Buthelezi."

In a statement released following a special National Working Committee of the African National Congress (ANC), the governing party said the downgrade by S&P must give impetus for government to redouble efforts to avoid similar decisions by the other ratings agencies. "We have noted the concerns raised by S&P in particular around the decisions to remove Comrade Pravin Gordhan, anxieties about perceived political instability and worries on whether the direction and trajectory of economic policy will change," the ANC said.

Government, the party added, remained "firmly committed" to sound and prudent financial management.

"The ANC has full confidence in the newly appointed Minister of Finance, Comrade Malusi Gigaba and the Deputy Minister of Finance, Comrade Sfiso Buthelezi. We will offer them our unequivocal support in executing the budget that was tabled by Comrade Pravin Gordhan following approval by Cabinet after thoroughgoing consultations. Any other expenditure, including on building nuclear capacity, will only be done at a pace and scale South Africa can afford, following stringent and transparent processes in line with the Constitution and other relevant laws."

The ANC-led government also remained committed to keeping the expenditure ceiling in the Medium Term Expenditure Framework intact and to the steps being taken to reinforce governance at the State-owned Companies.