Cape Town — Police investigators are trawling through a staggering 300 secretly taped conversations, mostly involving politicians, in Cape Town's Zillegate spy saga.

Police said it would take weeks to listen to all the conversations, taped between May and September.

The recordings were among items seized from the Parklands home of Phillip du Toit when police were investigating a hijacking.

The recordings and equipment found have led police to investigate a case of illegal interceptions.

The question being asked is whether Du Toit, a private investigator contracted to investigate Cape Town City councillor Badih Chaaban, may have bugged or illegally intercepted private communications.

Du Toit had been subcontracted by Neil van Heerden, a former police commissioner who owns a George Fivaz and Associates franchise, to carry out work for the city.

The recordings are said to be of an explosive nature, and are not all related to Chaaban.

A source close to the probe said Du Toit had been "very clever" in how he had carried out his work.

The last week has been one of high drama in the city as allegations surfaced that the DA used taxpayers' money to spy on their political opponents and alliance partners.

In response Mayor Helen Zille has sent out the terms of reference for a committee of inquiry. It appears to be much narrower in scope than the police investigation; (part of the investigation will be to investigate supply-chain management systems, the appointment of Fivaz and Associates, and that the city allegedly paid Fivaz for services rendered to the DA).

Premier Ebrahim Rasool is seeking answers to seven questions, which go beyond whether Badih Chaaban was spied on, why an underworld figure was employed to do the surveillance, and importantly, whether members of the city coalition were also spied on.

The DA's partners in the council, the Independent Democrats, have been assured by Zille and city Speaker Dirk Smit that George Fivaz and Associates had not spied on party members.

Yesterday Rasool met De Lille to tell her there was hard evidence to the contrary. De Lille will see provincial Police Commissioner Mzwandile Petros next week to hear the evidence.

The implications for the coalition in the city could be staggering, but De Lille said until proven otherwise, she had to believe they had not been spied on, adding: "We must find the truth.

"We started a process of getting to the truth and when we get there we will look at how we will take the matter further," De Lille said.