New information in documents, in the possession of Die Burger, shows that improvements to the estate have already cost the taxpayer almost R250m.
According to the documents, the department of public works has since 2009 spent R188m on building work, and paid R54m to consultants.
This brings the costs of the project to R247m. The original budget calculated in 2009 was R23m.
Bulletproof glass, elevator
A breakdown of spending on the Nkandla compound, which forms part of the public works department's prestige portfolio, includes R23m for “emergency work”.
Other payments include R121m to builders, R2.4m for bulletproof glass, R9.2m for a fence and a payment of R1.9m to a leading international elevator company.
Millions have already been paid to consultants, including architects, surveyors, engineers and project managers.
The presidency said in an earlier statement that the improvements to the compound were a family decision, paid for by the Zuma family.
Presidential spokesperson Mac Maharaj on Tuesday referred queries to the department of public works.
In turn, Sabelo Mali, spokesperson for minister Thulas Nxesi, referred Die Burger to a statement issued by the minister on October 1, in which he said all expenditure at Nkandla complies with guidelines in the ministerial handbook. He said the Nkandla compound is a national keypoint, which prohibits the release of any details of security arrangements.
In terms of an instruction approved by Cabinet in June 2003 and included in the ministerial handbook, the department can spend R100 000 on security improvements at the private houses of public officials.
Any costs above that must be covered by the official.
Approval of the full R100 000 is dependent on a security assessment by the South African Police Service at the request of the public official.
The handbook added that the official must make a formal application to the department of public works to contribute to security costs, after the assessment is complete.
Standard security improvements could include a bulletproof guardhouse, fences with vehicle and pedestrian gates, burglar guards on windows and doors, security lights, an intercom and alarm system and fire extinguishers.