"I, and other senior DA colleagues, have previously spoken at the New Age Business Breakfasts, under the assumption that the events were funded by the newspaper and by the members of the public who purchase tickets to attend," Zille said in a statement on Monday.
"Now that it has come to light that the breakfasts are funded by public money via the SOEs [state-owned companies] to the tune of millions of rand, the DA cannot continue to participate."
City Press reported on Sunday that some the biggest state-owned companies were paying millions of rands to bankroll the business breakfasts hosted by the Gupta family.
According to the report, Transnet paid R17.5-million for 18 breakfast sessions and Eskom R7.2-million to sponsor six sessions between November 2011 and last year. It was previously reported that Telkom sponsored 12 business breakfasts to the tune of R12-million in the 2012/13 financial year, according to the newspaper.
The SABC reportedly did not charge the New Age anything to broadcast their breakfasts live on SABC2.
Zille said she wrote a letter to the New Age editor Moegsien Williams on Monday morning informing him of her decision.
Bankrolling 'a privately owned newspaper'
"These breakfasts must be very profitable for the New Age, which is owned by the Gupta family, who are in turn vocal supporters and funders of the ANC and President Jacob Zuma," she said.
"It is not acceptable or defensible for public money to be used to bankroll a privately owned newspaper, and indirectly the coffers of the ANC."
This was especially true for Eskom, which was asking the public to pay more for electricity.
The New Age's chief executive Nazeem Howa responded to the City Press in Monday's edition of his newspaper.
"The latest attack on us in City Press yesterday comes at a time when we are starting to enjoy the fruits of our first two years of publishing ...
Our intentions are clear and public – we will be a major publishing force and we will challenge the incumbents in their negative approach to reporting on our new democracy," Howa said in a comment published on the newspaper's front page.
"We know that the attacks on us will increase as the impact we make in the market grows."
Both Transnet and Eskom defended their sponsorships of the breakfasts, according to the City Press report.
Transnet received a proposal, which it says was considered through the company’s normal channels, according to spokesperson Mboniso Sigonyela.
Eskom’s Hilary Joffe told the paper the decision to sponsor the briefings was reached after mutual discussion over a period of time. – Sapa