South African Revenue Service commissioner Tom Moyane told MPs on Tuesday that attacks on the organisation were damaging the South African economy as it had led to lower levels of tax compliance.

“Those who launch unwarranted attacks on Sars should know that they are impacting negatively on our economy,” he told Parliament’s joint standing committee on finance during a briefing by National Treasury and Sars on their quarterly reports.

Moyane added that perceptions that on his watch Sars has shed competent staff would turn into a “self-fulfilling prophecy” because it demoralises employees and prompt them to leave.

He made the remarks after complaining that the committee had timed the briefing poorly because March was the busiest month in Sars’s calender.

“It is defocusing us from the task at hand. March is the most important calender month in the history of this country.”

Moyane went on to remind MPs that Sars collected 90% of the money in the state’s coffers, and contrasted this with “extremely damaging and disrespectful” remarks about the state of the service, saying criticism was informed by bias.

But he baulked at questions from Democratic Alliance MP David Maynier about what the latter termed a “civil war” between himself and Finance Minister Pravin Gordhan. Pointing out that English was his “third or fourth” tongue he said he could not comment on a phrase that to his mind evoked the bloodshed seen in Somalia.

Moyane said he wanted to debunk the claim that Sars had a R30-billion collection deficit in the current financial year. He asked Sars group executive Randall Carolissen to explain that the figure was based on a revenue forecast that has since been adjusted downwards, from R1.175-trillion to R1.144-trillion.

“Let me speak to the issue of the tax revolt. So that the report end of December, today we have much better information… up to December our growth rate was seven%, so we were well on our way to meet even our target in the MTBPS [medium-term budget policy statement]. Our growth rate for February year on year was only 1.7%, and that brought the year-to year growth rate down to 6%,” said Carollisen.

Carolissen said revenue figures for February were partly the result of a dismal picture as far as imports were concerned in January. But he said Sars believed it was, with days to go to the close of the financial year, still within reach of the revised revenue collection target of R1.144-trillion for the year.

The briefing came amid intense speculation that President Jacob Zuma is poised to fire Finance Minister Pravin Gordhan after ordering him to return to South Africa from an international investor roadshow in London.

Neither Moyane nor Gordhan have sought to dissimulate tension between them.

Asked by MPs on Tuesday how this impacted the fact that the head of Sars reported to the finance minister, he replied that he was appointed by the President.