Seven officials at the Nelson Mandela Bay Municipality have been placed on precautionary suspension after an internal investigation into fraud and corruption.

Nelson Mandela Bay Mayor Retief Odendaal said the electricity and energy directorate officials were suspended following a "preliminary investigation into allegations of fraud and corruption" that was started after a recent explosion at an electricity substation at the Coega Industrial Development Zone.

The initial investigation, which was done through an internal audit, was handed over to the Hawks and the Special Investigating Unit (SIU) for further investigation, said Odendaal.

"We believe that we are on the brink of uncovering one of the biggest corruption networks in the administration to date, which has potentially siphoned millions of rand from City coffers over the last few years," he added.

PE Express previously reported that the explosion took place on Saturday, 11 March and led to an electricity blackout of surrounding areas.

After the explosion, Electricity and Energy MMC Lance Grootboom said the municipality was not certain if the cause of the explosion was foul play or vandalism.

"I reported at the time that the municipality would launch a full-scale investigation to uncover how the explosion occurred. As a result, the City instituted a forensic investigation into the matter that uncovered alleged irregularities, fraud and corruption," Grootboom said.

The damage to the substation infrastructure is estimated at more than R40-million.