Some of South Africa's most high-ranking police officers have been exposed as murderers, rapists and thieves but none have yet been fired, officials have admitted.

Opposition MPs said the revelation that crime fighters are themselves criminals demonstrates "serious mismanagement" of the police, whose reputation remains badly damaged by the massacre of 34 striking mineworkers at Marikana one year ago on Friday.

The parliamentary portfolio committee on police heard that a major general, 10 brigadiers, 21 colonels, 43 lieutenant colonels, 10 majors, 163 captains and 706 warrant officers have been found guilty of serious offences.

In total 1,448 members of the police have convictions, according to an audit up to January 2010. The crimes include murder, attempted murder, culpable homicide, rape, attempted rape, assault, aiding an escapee, theft, housebreaking, drug trafficking, kidnapping, robbery, malicious damage to property and domestic violence.

Nkrumah Mazibuko, the police's head of personnel management, told the committee that 306 officers had been convicted before they joined the police. The remaining 1,142 had been convicted while purportedly working to uphold the law. Some had even used false fingerprints to cheat the vetting procedure.

Even those who are caught out cannot be dismissed instantly, Mazibuko admitted on Wednesday. "They go through a disciplinary process, appeal, and we are ordered to reinstate them. If the person appeals the sentence and it is reduced to a suspension then, in terms of our own act, the person is entitled to apply for reinstatement."

To prevent more cases in future, the police intend to vet all recruits more closely, take disciplinary action as soon as an officer is arrested and make it compulsory for all police employees to declare their criminal status.

MPs condemned the findings. Annelize van Wyk, the chair of the police portfolio committee, expressed dismay that "we are expected to, and South Africa is expected to, sit back and accept that 1,448 identified criminals must still be paid for another year with taxpayers' money, must still carry a firearm, and must still wear the blue that should be worn with pride".

Dianne Kohler Barnard, the shadow police minister for the opposition Democratic Alliance, accused the police of "serious mismanagement". She said: "In fact, the vast majority of the 1,448 are top brass. All are still employed by the Saps [South African Police Service] today and have yet to be fired.

"The 1,448 leaves out details of the other 8,000 police officers who were excluded from the audit because they had already been fired or their crimes were considered petty offences. Any offence is an offence and the police should be held to a higher standard."

None of the police directly involved in the Marikana shootings have been arrested or put on the witness stand at the slow-moving judicial commission of inquiry. In the past year police brutality has also been put in the spotlight by incidents including the killing of a Mozambican taxi driver who was dragged handcuffed behind a moving police van.

David Bruce, a leading independent researcher, estimated that the 1,448 officers with criminal records are about 1% of the entire force but the true figure is likely to be "drastically" higher.

He said: "Police brutality is widely practised in various forms. If the mechanisms for investigating it were more efficient, there would be many more officers who would have criminal records for offences of that kind."

He added: "The reputation and name of the South African police is profoundly tarnished, not just by the Marikana massacre itself but evidence that emerged of interference at the scene. There is a serious problem of police credibility."