South African President Jacob Zuma expressed concern Wednesday over damaging allegations that he benefited from unlawful renovations at his private home worth $23 million, a bill picked up by taxpayers.

Facing a deadline to respond to a scathing report by the public protector that comes just weeks before South Africans go to the polls, Zuma's office said he "remains concerned about the allegations of maladministration and impropriety."

Public protector Thuli Madonsela said the upgrades -- which include a helipad, swimming pool, amphitheatre, private clinic and visitors' centre -- were unlawful and said Zuma should refund taxpayers.

Zuma, 71, whose popularity is flagging, pointedly refused to comment in detail about the substance of the report.

Instead he put the public protector's findings on an equal basis as two other reports into the scandal which critics claim may be more favourable, including one by his own ministers.

Zuma indicated he would not comment in full until the third report, by the Special Investigating Unit -- a body established by presidential proclamation -- was completed.

A statement said Zuma would then give "full and proper consideration" to the reports and inform parliament about "decisive executive interventions."

The main opposition Democratic Alliance accused Zuma of "playing games with the parliament" and said Wednesday's statement was "nothing more than a delaying tactic."

"The truth is that President Zuma is running away from accountability. We won't let this happen without a fight," said the party's parliamentary leader Lindiwe Mazibuko.

The Democratic Alliance has launched a criminal corruption case against Zuma over the upgrades and plans impeachment proceedings.

"We will continue to push on with our impeachment motion, and we will continue to seek legal advice on what steps can be taken to force the President to abide by these recommendations," said Mazibuko.

The newly-founded Economic Freedom Fighters, led by the erstwhile leader of the ANC youth league, Julius Malema, also laid charges of corruption, theft, fraud and racketeering against Zuma in Pretoria.

Malema was in 2012 expelled from the ANC for fomenting divisions within the party.

Earlier this week Zuma shifted blame for the overspending to government officials.

"They did this without telling me," he told local television channel ANN7. "So why should I pay for something I did not ask for."

Despite being Africa's largest economy, South Africa still has widespread poverty and 10 million people live on government aid.

Zuma will seek a second five-year term on May 7, in elections that are expected to be South Africa's most fiercely fought since 1994, when apartheid ended.