The head of the Special Investigating Unit (SIU), Willie Hofmeyr, on Thursday expressed frustration that government failed to deal decisively with cases of corruption identified by his staff.

"There are cases of a really serious nature where disciplinary action does not take place," Hofmeyr told Parliament's watchdog Standing Committee on Public Accounts (Scopa).

Calling disciplinary processes "a weakness of government", Hofmeyr said that even when they were initiated, "I'm afraid they seldom run to a conclusion".

"With serious cases one should look at whether government should not have a central mechanism to drive these processes."

He said the lack of action was one of the "frustrations" of the unit and hinted that progressive labour legislation might be a factor preventing government from firing corrupt officials.

The SIU is one of the main agencies fighting corruption, which President Jacob Zuma's administration has listed as a top priority.

It was established in 1961 with a staff complement of 67 which has now grown to nearly 600 and will be expanded to one-thousand.

Hofmeyr's point was underscored when in a subsequent briefing Correctional Services Minister Nosiviwe Mapisa-Nqakula told Scopa that she regretted the disciplinary action against suspended National Commissioner Xoliswa Sibeko had "dragged on and on" only to deliver an outcome she would have liked to challenge but did not for fear of wasting more time.

Mapisa-Nqakula pointed out that after Sibeko was suspended in July last year for using taxpayers' money to rent a house for R34 000 a month despite having an official residence, the department's investigation took only two weeks to complete.

It found that there was an abuse of procurement policy but Sibeko challenged this and was cleared after a disciplinary hearing in November.

"I'm sure you are aware that the commissioner won her case," Mapisa-Nqakula told Members of Parliament (MPs), adding that she had been "tempted" to take the matter further.

"But if I had taken it on review it would have taken even longer," she said.

"That is a problem of our own laws which we have put in place.

The minister said it prevented departments from taking quick action and "firing the person" if necessary.

"We have got to put a process in place that will enable us to act fast to determine whether a person is guilty or not."

Sibeko was on full pay while she was suspended. After the hearing, Mapisa-Nqakula put her on special leave.

"The minister asked her to remain on special leave while she applies her mind to the situation," spokesperson Sonwabo Mbananga said.

The minister indicated to MPs that she would like to have the situation resolved rapidly, saying: "I hope we do not have an acting commissioner for very long."

She appeared before Scopa with a team of correctional services officials who were grilled about the department's annual report and its efforts to root out corruption.

Earlier this month, Zuma reportedly indicated that he wanted government to do away with lengthy disciplinary processes and suspending corrupt civil servants on full salary.

His party spokespesron Zizi Kodwa said that the President was frustrated with the impact this had on service delivery and hoped to persuade the Congress of South African Trade Unions that labour laws should be changed in this regard.