South African Revenue Service (Sars) commissioner Tom Moyane says he asked the State Security Agency (SSA) to uncover the source of confidential Sars documents leaked.

He said this investigation was not related to confidential letters between him and Finance Minister Pravin Gordhan which the Mail & Guardian reports on in this week’s edition.

This week’s M&G reveals details of 16 letters –  dating back to April – which prove the strained relationship between the two men.

During a press conference in Pretoria this morning, Moyane briefed the media on Gordhan’s earlier statements about a R30.4-billion revenue shortfall and shortcomings at Sars.

“We must demystify the myth that Sars is dysfunctional. I have a dim view of someone saying Sars has no adequate leadership,” he said.

While Moyane’s office did not respond to questions from the M&G, he and his senior team did address some of the key issues emanating from the letters.

This includes that he had authorised his own bonus, something Gordhan had billed in one of the letters as “immoral” and “unethical” if done without approval and in the absence of a performance review.

Moyane told the media that he had not paid himself a bonus.

He also confirmed that his relationship with Gordhan was “strained”.

Moyane and Sars executives responded to questions about the brain drain from the revenue service, delayed value added tax refund payments and requests for President Jacob Zuma to intervene to contain the ongoing hostility between Moyane and Gordhan.

Moyane took direct, personal credit for approaching the SSA to investigate a leak, saying it was important for an “independent institution” to “be able to find out where the source of the leakage emanates”.

The SSA could not on Friday immediately comment on the matter, but Moyane, when asked for clarity on the investigation, later told the M&G that the SSA investigation did not involve the 16 letters revealed by the M&G but rather, an unspecified earlier incident. On those findings, he said: “We have conclusive proof … this therefore concludes and closes that chapter on this particular incident.” he said.