Unions representing hundreds of thousands of workers including nurses vowed to stage picket lines and demonstrations outside hospitals, ports and government offices in a "show of force" next Tuesday.
"With the rapidly increased cost of living... the government wants public servants to be at peace with less than inflation increases. This cannot stand," the unions said in a joint statement.
They want wages to rise by up to 10 percent, amid high inflation.
Inflation in South Africa was at 7.5 percent in September, down from a peak of 7.8 percent in July.
Earlier this month, Labor Minister Thulas Nxesi said the government would unilaterally implement a three percent increase across the board -- an offer dismissed by workers' representatives as "paltry."
Finance Minister Enoch Godongwana said during his October mini-budget speech that the government could only afford an average wage increase of 3.3 percent.
The unions called on all their members, including essential workers such as police officers, to march on the National Treasury's offices in Pretoria and join protest actions across the country next week.
"We have resolved to rally our collective might to push the employer to improve the rejected offer and will use everything in our power to register our disdain to the government," they said.
The call for action comes after thousands of public workers struck last week in one of the largest work stoppages in recent years.
It also risks adding to the country's economic and social woes including high unemployment, surging crime and a restive population.
The dispute between the government and its employees piles pressure on President Cyril Ramaphosa, as he seeks re-election as leader of the ruling African National Congress (ANC) party.
Ramaphosa, who also faces accusations he attempted to cover up a multi-million-dollar cash theft at his farmhouse, seeks a second term at the helm of the ANC.
The party will pick a new leader in hotly contested internal polls in December.