"This is the first of many investigations that will need to be initiated to ensure that the President is held fully accountable for his exorbitant and unnecessary cash splurge of taxpayer's money," said DA parliamentary leader Lindiwe Mazibuko.

City Press reported that Public Protector Thuli Madonsela had opened the investigation into Zuma's home in Nkandla.

"Yes, an investigation is under way," Madonsela told the paper.

Madonsela said her office began preparing for an investigation after an official complaint was made a few months ago.

She said Mazibuko also made a complaint last week.

"Because of our resource constraints, the investigation hasn't gone further than contacting the presidency," Madonsela told the paper.

"We are asking the presidency who makes what decisions and who is accountable. This involves more than just [the department of] public works.

On Friday, Public Works Minister Thulas Nxesi said the upgrades at Zuma's residents were similar to those of former presidents.

He declined to disclose how much money had been spent on the security and other constructions.

So far, high security fences had been erected, roads in the area had been upgraded and local fire fighting services had been developed for the helipads.

Reports have estimated the cost of the work to be between R203 million and R238 million.