The South African military was put on high alert on Wednesday when former ANC official Julius Malema addressed disgruntled soldiers in the Johannesburg area.
It was the first time since South Africa became a democracy in 1994 that the government has issued such an order.
Mr Malema told the soldiers to mobilise in a disciplined way to save their jobs.
The soldiers he addressed were suspended from the South African National Defence Force after rioting in the capital, Pretoria, in 2009 to demand higher wages.
Mr Malema was expelled from the African National Congress party in April and is under investigation for alleged corruption.
He has been touring mines since the killings at the Marikana platinum mine on 16 August, calling for a national strike and for the mines to be made "ungovernable".
Thirty four miners died at Marikana that day. Police said they acted in self defence. Two police officers were killed by strikers the previous week.
Mr Malema is campaigning for President Jacob Zuma to be ousted as ANC leader at the party's national conference in December.
A BBC correspondent says South Africa is in a jittery mood, partly because of fears that labour unrest could spread, and partly because the government appears preoccupied with infighting, as factions plot to unseat the president.
On Tuesday, Mr Malema called for strikes at all mines for five days each month, to fight for an increase in pay of three times the current national average.