South Africa's largest union has called for more than 200,000 engineering and metals workers to lay down tools for higher wages from July 1, just days after the mining sector ended a five-month strike.
The National Union of Metalworkers of South Africa (NUMSA) said on Thursday that it had "agreed to the decision from our members to embark on an indefinite strike action, beginning on July 1, 2014".
"We are going to strike, we are going to bring the industry to a standstill," said Karl Cloete, the deputy general secretary of the Numsa.
Cloete said wage negotiations in the sector were deadlocked, with workers demanding a 12-percent wage increase, reduced from an initial demand of 15 percent.
More than 220,000 workers of Numsa's 340,000-strong members will down tools in the key power generation, electrical engineering, telecommunications, steel and plastic fabrication industries.
Employees of the car-manufacturing industry, which already suffered serious stoppages last year, will not take part in the strike, but the sector is likely to be affected when component workers down tools.
It's not our intention to plunge the country into darkness by embarking on a strike
Numsa also called for a stoppage at Eskom, the state-owned power utility, paying negotiations were deadlocked over the firm's proposed wage increase of 5.6 percent for its 10,000 staff.
South Africa's public utility workers are banned from striking because their industry is classified as essential service.
But Numsa dismissed the ban, saying its members there were not "intimidated by threats of the illegality of our actions".
"It's not our intention to plunge the country into darkness by embarking on a strike," said Cloete, referring to the impact the strike might have on Eskom, which supplies around 95 percent of South Africa's electricity.
The firm has struggled to keep the lights on in Africa's most developed country and is already behind schedule in the construction of key power plants to ease the problem.
The union said the strike call was "part of a tactic to exert organisational pressure on the bosses to return to the table and present an offer acceptable to our members".
Wage negotiations in the sector were started in March this year.
Numsa said workers in the sector were demanding a 12-percent wage increase, nearly double the inflation rate of 6.6 percent.
Cloete said the union will not accept a settlement of less than 10 percent.
The union is one of the biggest critics of the government's labour and economic policies, arguing that they do not benefit the poor.
The union has also severed ties with the ruling African National Congress (ANC), announcing plans this year of launching a workers' party.
Mid-year is know as "strike season" in South Africa, when several sectors negotiate wage contracts with employees.