The Presidency has announced three more departures by senior officials in its office but denied that there was a "crisis".

"There is no exodus of staff, and there is no crisis or turmoil in the institution," the Presidency said in a statement posted on its website on Monday.

"What is happening are normal staff movements as it happens in any organisation at any time," the Presidency said, adding that it was concerned about "speculative reporting" on staff changes.

The comments were contained in a statement entitled, "Staff changes in the Presidency", which confirmed weekend rumours of more departures by senior officials.

The statement said that President Jacob Zuma's economic adviser Mandisi Mpahlwa and deputy director-general for communications Vusi Mona would move to other jobs.

The Presidency said that Mpahlwa had been appointed ambassador-designate to the Russian Federation.

"Given the importance of Russia, we needed a seasoned cadre to represent the President and the national interest in that country," said the Minister in the Presidency responsible for Performance Monitoring, Evaluation and Administration, Collins Chabane.

Mpahlwa will assume the post in September.

Mona will move to the Government Communications and Information System.

"The weekend media reports that Mr Mona has been asked to resign are incorrect," said the statement.

"Meanwhile, President Zuma and Minister Chabane are currently in discussions with the director-general, Mr Vusi Mavimbela regarding his role and this has not been finalised yet."

The resignation of chief director for Presidential support services Steyn Speed - "who is leaving to undertake further studies" - was also announced in the statement.

Zuma spokesperson Vincent Magwenya resigned last week to "rejoin the corporate world".

Chief operating officer Jessie Duarte resigned in April.

At the time, the then deputy director-general in the Presidency - and now chief of staff - Lakela Kaunda, dismissed reports linking her to Jessie Duarte's resignation as "grossly incorrect" and "unfortunate".

"I have never had a quarrel with Ms Jessie Duarte," said Kaunda at the time.

In February, it was reported that Duarte wrote an "emotional email" to African National Congress secretary-general Gwede Mantashe, citing a "smear" campaign, "gossip" and "vilification" as reasons for intending to leave.