Operations of South African Airways (SAA), the country's national carrier, have been suspended with immediate effect.
"This means SAA will complete repatriation flights that have already been scheduled but will not schedule any further flights," Business Day news site reports.
Administrators said they were putting the struggling state-owned carrier under "care and maintenance" until funding for a restructuring plan was found.
The airline was put in bankruptcy protection in December after heavy financial losses in the past few years, which have been exacerbated by the Covid-19 pandemic.
The government has not come up with more than 10.5bn rand ($621m; £483m) to support a restructuring plan outlined by administrators in June, EWN news site reports.