South Africa's government is seeking a judicial review into a report which said President Jacob Zuma should repay some of the $23m (£14m) used to upgrade his home.
The report, published in March by a government ombudsman, said the president had "unduly benefitted" from the renovations at his home in Nkandla.
The government has always said the work was needed to improve security.
It included building a swimming pool, cattle enclosure and chicken run.
In a statement, the government's security ministers said "some of the findings and remedial action proposed by the Public Protector in her report are irrational, contradictory and are informed by material errors of law".
Public protector Thuli Madonsela responded by saying "she could not imagine any court of law finding in the ministers' favour", the AFP news agency reports.
She was last month named as one of the 100 most influential people in the world by the US Time magazine.
The main opposition party, the Democratic Alliance, has laid corruption charges against Mr Zuma over the use of taxpayers' money to upgrade his Nkandla residence.
While many South Africans were angered by the report, Mr Zuma's African National Congress still won an emphatic 62% of the vote in elections earlier this month.
The DA came second with 22%.