South African union leaders have threatened to call a nationwide strike across all sectors of the economy in support of public workers, whose pay dispute is in its ninth day.
"Everything will come to a standstill," said Zwelinzima Vavi, head of the main union federation, Cosatu.
He was speaking at a rally of thousands of public workers in Johannesburg.
Some one million civil servants are already on strike but Cosatu's total affiliated membership is double that.
Mr Vavi said work would also halt in the key mining and manufacturing industries, while unions representing the police and the military have already said they will join in the stoppage.
"Today, on 26 August, all Cosatu unions will be organising all their workers to issue notices to employers that they will be joining the public sector strike," he said, according to the South African Press Agency (Sapa).
"We will not be defeated," he told cheering protesters in Johannesburg.
Cosatu is officially an ally of the governing African National Congress but Mr Vavi warned that their alliance was now "dysfunctional".
A court has, however, barred police officers from joining the strike. Officers who went on strike could be fired, police said.
A previous court injunction ordered the unions to keep essential services going.
Workers want an 8.6% pay rise, and are angry the government offered 7%.
In the commercial hub of Johannesburg, hundreds of protesters, many wearing red T-shirts, sang and danced as they marched through the streets.
At the march, the BBC's Karen Allen spoke to teachers with 20-25 years' experience, who say they cannot live on their salaries of approximately $6,000 (£3,870).
Meanwhile, thousands of public servants marched to parliament in Cape Town.
The protesters have been angered by recent newspaper stories of corruption and lavish spending by ministers.
The government says it cannot afford to deliver wage increases that amount to twice the rate of inflation.
Our correspondent says there is little sign of any movement in the negotiations.
Despite the threat to strike, police officers were monitoring the protesters in Johannesburg in case of any trouble.
Police and Prisons Civil Rights Union spokesman Norman Mampane said union lawyers would challenge the order, reports the AP news agency.
The police have previously been involved in violent clashes with some strikers and have fired rubber bullets, water cannon and tear gas at the protesters.
Last weekend, another court ordered the unions not to disrupt emergency services.
Military doctors have been deployed around the country to keep hospitals open, but the South African Security Forces Union has asked the government to resolve the dispute quickly, saying that the military should not be used for substitute labour.
The health ministry has asked for volunteers to help clean hospitals and cook food for patients.
Many schools around the country are closed.
President Jacob Zuma has defended the unions' right to strike but also urged them to end violence and intimidation.