Polygraphs in South Africa: Legal Status, Application & Case Successes in the CCMA and Labour Court

Polygraph tests—commonly referred to as lie detectors—are increasingly used by South African employers in disciplinary investigations. While there is no statute specifically regulating them, polygraphs are legally permitted under strict conditions, and may play a valuable supporting role in proving misconduct.

Used correctly, polygraph results have even contributed to decisions made on a balance of probabilities, which is the standard of proof in labour disputes. However, misuse or overreliance can lead to rulings of unfair dismissal.

Legal Status & Admissibility

• South Africa has no specific legislation governing workplace polygraph testing. However:
• Polygraphs are not prohibited.
• Testing must be voluntary and conducted with written, informed consent.
• Forcing an employee to take a polygraph may infringe constitutional rights like privacy and protection against self-incrimination.
• At the CCMA and Labour Court, polygraph results are admissible, but:
• They cannot stand as sole evidence of guilt.
• They are accepted only as corroborative or supporting evidence, aiding the employer’s case on a balance of probabilities.

Key Case Law: DHL Supply Chain v De Beer (LAC)

• The Labour Appeal Court clarified that:
• Failing a polygraph does not prove guilt.
• If relied upon, the employer must lead expert evidence to confirm:
• The qualifications of the examiner.
• The scientific reliability of the test.
• This case affirmed that polygraphs can assist in disciplinary outcomes, but must be used in combination with other evidence to support conclusions on the balance of probabilities.

When Can Employers Use Polygraphs?

• Employers may request polygraph testing when:

1. Voluntary & Written Consent

• The test must be entirely voluntary and the employee must sign consent documentation.

2. Reasonable Suspicion & Access

• There must be reasonable suspicion of misconduct (e.g., theft, fraud), and the employee must have had opportunity or access to the assets involved.

3. Fair & Transparent Process

• Inform employees in writing.
• Allow interpreters or observers.
• Use a qualified, impartial examiner.
• Ensure test questions are pre-agreed and relevant.

Successful Use of Polygraphs in Labour Disputes

• Govender & Chetty v Container Services (CCMA)
• The commissioner accepted polygraph results, combined with circumstantial factors, as sufficient on a balance of probabilities to uphold dismissal, even without direct evidence.
• Metal & Electrical Workers Union v Mbonambi (CCMA)
• Polygraph results supported by witness testimony and inconsistent explanations helped establish guilt on a probability basis.
• Amalgamated Pharmaceuticals Ltd v Grobler NO (Labour Court)
• Polygraph results were allowed as corroborating evidence—they helped establish employer credibility and suspicion in a dismissal case.
• FAWU obo Kapesi v Premier Foods (CCMA)
• Polygraph results, linked to clear access and opportunity, were considered alongside employer testimony to justify dismissal on balance of probabilities.

Polygraphs & Balance of Probabilities

• In South African labour law, the standard of proof is not “beyond reasonable doubt,” but “on a balance of probabilities.”
• This means:
• An employer must show that the version pointing to the employee’s guilt is more likely than not.
• When combined with credible evidence—like inconsistencies, motive, or witness statements—a polygraph result may tip the scale in favour of the employer’s version.
• The key is that the test result supports, rather than defines, the narrative.

Best Practice for Employers

• To make effective, lawful use of polygraph testing:
• Never rely solely on a failed polygraph—gather and present other supporting facts.
• Use a certified polygraphist and retain them as a possible expert witness if needed.
• Ensure procedural fairness: give notice, obtain consent, allow employee representation.
• Prepare for scrutiny at the CCMA or Labour Court—be ready to explain why the test was needed, how it was conducted, and what other evidence supports your case.

Conclusion

Polygraph testing remains a lawful investigative tool in South Africa, but only when used correctly. Courts and the CCMA have made it clear: results may help support findings on a balance of probabilities, but can never be the only reason for dismissal.

For employers, polygraphs should be viewed as part of a holistic investigative approach—not a shortcut to conclusions.