The Twitter account of the State Security Ministry was hacked at the weekend, according to a report.
The Cape Argus reported that a hacker gained access to the account on Saturday night and uploaded a tweet advertising a "miracle diet", with a link to a website with more details.
The tweet stated: "Fastest way for processing fat off your body in two weeks".
The online community was quick to respond.
"Ooh, hope the password wasn't 'secret', hey," tweeted Gaye Davis.
According to the newspaper, Democratic Alliance defence spokesman David Maynier joked that the diet website offered some good advice, but even with the department's broad definition of national security, it would be difficult to include the country's diet as a safety concern.
"One would expect that the department responsible for protecting the state from cyber attacks would be hacker proof," he reportedly said.
Department spokesman Brian Dube confirmed to the newspaper that the account had been hacked and said officials had changed the password as soon as they realised what had happened.
