Faf du Plessis's men lost 60% of their match fee. © AFP

South Africa have been penalised six ICC World Test Championship points and fined 60 per cent of their match fee for maintaining a slow over rate against England in the fourth Test match at the Wanderers.

Faf du Plessis's side was found three overs short of the target after time allowances were taken into consideration by match referee Andy Pycroft.

The charges were levelled by on-field umpires Bruce Oxenford and Joel Wilson, third umpire Rod Tucker and fourth official Allahdien Palekar. Du Plessis pleaded guilty to the offence and accepted the proposed sanction, so there was no need for a formal hearing.

"In accordance with Article 2.22 of the ICC Code of Conduct for Players and Player Support Personnel, which relates to minimum over-rate offences, players are fined 20 per cent of their match fees for every over their side fails to bowl in the allotted time," the ICC release clarified. "In addition, as per Article 16.11.2 of the ICC World Test Championship playing conditions, a side is penalised two points for each over short."