An investigation into tender irregularities relating to the decomissioning of the Athlone Power Station has revealed evidence of possible corruption, Cape Town Mayor Patricia de Lille revealed on Thursday.

The ANC raised concerns around the awarding of a multi-million rand tender to engineering firm, Aurecon.

In February of that year, the bands on one tower collapsed, prompting the city to announce that the structures would be demolished by the end of April to prevent their collapse.

De Lille said her office wrote to Aurecon late in 2012, requesting information on the tender.

This after a forensic audit was conducted.

The firm's lawyers had requested an opportunity to gather evidence from the city in terms of the Promotion of Access to Information Act.

The council agreed to share the information.

Aurecon has until the end of the business day to submit its formal response.

De Lille said action against implicated officials had already been taken.

The ANC says it has been vindicated.