The Democratic Alliance (DA) will go to court in an effort to force the public works department to hand over its report on the upgrades at President Jacob Zuma's private residence at Nkandla, the party said on Monday.
The department "classified" a report into the spending on Zuma's residence, ostensibly because making the information public was a threat to national security.
In August, Public Works Minister Thulas Nxesi told Parliament the report could not be released to the public works portfolio because "it is insensitive to request a document that deals with the security of the head of state. It is as simple as that".
On Monday, Mazibuko said the report was not classified under any law, and efforts by the department to keep it under wraps were therefore illegal.
The DA applied for access to the "classified" report under the Protection of Access to Information Act (Paia), but this was rejected, Mazibuko said.
The party wants the rejection of its application to be declared invalid and unlawful; the rejection of its appeals (against the rejection of its Paia application) to be declared invalid and unlawful, and for the court to force the department to hand over the Nkandla report within five days.
"It is over a year later we are still in the dark about how hundreds of millions of public money benefited one man," Mazibuko said.
Meanwhile, Monday was also the final deadline for information on Nkandla to be submitted to the public protector, Thuli Madonsela. On September 25, Madonsela indicated that her report into the spending was almost complete, but that she was waiting for information from "one party".
"A comprehensive request for information was launched on August 11," she said.