Responding to a question from the Democratic Alliance, Brown confirmed that Eskom paid the PPF, headed by firebrand former Cabinet spokesman Jimmy Manyi, R40 000 for seats at a gala dinner in 2015 and R400 000 last year.
Transnet gave the PPF R400 000 in similar fashion.
Manyi recently made headlines with his vehement opposition to the Financial Intelligence Centre Amendment Bill, telling Parliament's standing committee on finance that the draft law was aimed at blacklisting African National Congress (ANC) donors and bankrupting the ruling party.
Democratic Alliance finance spokesman David Maynier suggested that the sponsorships were an attempt by former Eskom CEO Brian Molefe, who previously headed Transnet, to boost the PPF while it publicly undermined National Treasury to curb misspending of public funds.
Molefe openly clashed with Finance Minister Pravin Gordhan while National Treasury was probing Eskom's coal contracts, including with the Gupta-owned company Tegeta.
"What this reveals is that Brian Molefe, who headed up Eskom at the time the 'sponsorships' were made, was effectively funding an organisation which was waging a 'dirty war' on the Minister of Finance, Pravin Gordhan, and National Treasury, as they probed suspicious contracts entered into by Eskom," Maynier said.
He added that it was improper for any parastatal to give money to the PPF, and said he would ask Auditor-General Kimi Makwetu to investigate the sponsorships.