"We are going ahead with the strike action," said Sam Shilowa, general secretary of the Congress of South African Trade Unions (Cosatu).
Investors have cited concern about the impending one-day strike among reasons for the decline of the South African rand to record lows last week. The rand brightened briefly yesterday at 4.30 to the dollar, but later weakened to 4.35, with dealers saying the market was still waiting for clearer signals from the government on the direction of economic policy.
Mr Shilowa said that despite President Mandela's effort on Sunday to broker a settlement, Cosatu remained opposed to constitutionally negotiated positions on employers' right to lock out workers, protection of property, education and the status of the 11 official languages.
He said a four-hour meeting yesterday with Cyril Rama- phosa, the ANC secretary-general, had also failed to reassure Cosatu, the country's largest trade union federation.
"Based on all these issues, we are taking to the streets tomorrow. We are confident that our membership will respond," he said and predicted solid support for the mass action.