Democratic Alliance leader Helen Zille on Wednesday shed more light on donations worth R400,000 from an associate of the Gupta family and one of their companies.

Addressing reporters at Parliament, Zille did not deny writing a letter, published in The New Age (TNA) newspaper, in which she thanks Atul Gupta for a donation to her party.

TNA is owned by the Guptas, who are believed to have ties to President Jacob Zuma.

Zille explained the letter was sent before she was informed a R200,000 donation, received in 2009 for the party's election campaign, came from Stefan Nel, a Sahara Computers executive director.

The Guptas own Sahara and Atul Gupta is the company's managing director.

Zille said she was under the impression the cheque came from Sahara and not Nel in his personal capacity.

Until now, Zille had not named the donor, citing a promise to maintain confidentiality.

Zille said Nel later wrote another cheque for R100,000 to the DA. The party also received an electronic transfer of R100,000 from Islandsite Investments, which is also linked to the Gupta family.

Zille insisted there was nothing wrong with the donations, as there was no scandal involving the Guptas when the money was accepted in 2009 and early 2010.

She later instructed the DA's fundraising department "to have nothing to do with the Gupta family or any of their companies".

"Early in 2011 when I started getting concerned they [the Guptas] may be channelling money to the DA via Mr Nel, I gave instructions, that's in the file, [that there will be] no more fundraising from Mr Nel... It's all recorded."

Zille said the DA would not return any of the money.

Also on Wednesday, Zille said she wanted an independent probe into the funding of TNA newspaper.

"I have today written to President Jacob Zuma to request that he appoint a judicial commission of inquiry, headed by a retired judge, to investigate the funding of The New Age."

She said the newspaper was almost entirely funded with taxpayers' money, and claimed 77 percent of its advertising revenue came from national and provincial government departments, and state entities.

She drew parallels with the apartheid-era scandal involving The Citizen, which was set up and funded with state money.

"All the evidence points to the same thing: the ANC are using public money, both overtly and covertly, to fund a newspaper which is openly favourable to their government."

Zille and TNA executives have been engaged in a public spat, after she refused to speak at one of their business breakfasts because it was being funded with public money.