Former treasury director general Lungisa Fuzile has told the commission of inquiry into state capture that changes in finance ministers in recent years were not meant to strengthen the National Treasury but to weaken it.
"Frequent changes to ministers...one made the point [that] it takes a lot to learn to work with each politician because each one of them has different styles.
"When they change frequently it is very hard to keep focus on the work," Fuzile told inquiry chair Deputy Chief Justice Raymond Zondo during his testimony on Monday.
"Some of the changes could never be meant to strengthen the National Treasury, they were meant to weaken it.
"I feared that having been part of building it for 18 or 19 years, I couldn't also be part of seeing it getting weak. I would rather watch it from the outside even if with a sore heart," Fuzile testified.
Fuzile said when ministers were axed, he would wonder what the reasons were.
Fuzile elaborated on why he decided to resign from National Treasury - one of the country's most respected institutions.
He explained to the commission that he knew it was time to tender his resignation when a delegation he was part of was instructed to return from an investor roadshow in the UK.
Minister Pravin Gordhan and his deputy at the time, Mcebisi Jonas, were leading the delegation to meet investors and ratings agencies.
At the time, Treasury officials had been expected to spend two days in London before flying to Boston and New York in the US.
However, a "dodgy" intelligence report allegedly sparked the reshuffle that resulted in Zuma demanding that the ministers cut the trip short and return home.
Gordhan, Jonas and other ministers were axed in Zuma's infamous late-night Cabinet reshuffle in March 2017.
"I had kind of made up my mind, in my case, from the time we were called back that my time for serving as director general was up," he said.
He also added that he tendered his resignation because "I reached the end of the runway".
Asked by advocate Vincent Maleka, SC, about what had caused him to resign, Fuzile said there was no chance of making a positive difference.
"I had made up my mind that after all the changes that I had encountered with ministers, not because of any loyalty to Minister Gordhan, but I just decided that he was going to be the last minister that I would serve under."
The commission continues on Tuesday with testimony from National Treasury economist Catherine MacLeod.