JOHANNESBURG: Tens of thousands of builders halted work and aircraft technicians disrupted air traffic on Monday in the latest strikes to hit South Africa, fanning fears of new violence.

Around 90,000 construction workers embarked on an indefinite strike demanding a 13 per cent pay increase, against employers' offer of six per cent.

Two people were reportedly stabbed during a workers' protest in Johannesburg's plush suburb of Sandton, police said.

The South African government warned the strikers to stay “within the ambit of the law”, threatening to act against “those that contravene the country's laws.”

“It is unacceptable when people's rights are violated by perpetrators of violent actions,” authorities said in a statement, urging employers and workers to “engage in meaningful dialogue and to speedily reach an agreement.”

Violent labour disputes last year claimed over 50 lives at South Africa's platinum mines, including 34 miners shot dead by police in one day at Lonmin's Marikana mine.

Now as construction workers down tools, union federation Cosatu said employers could well afford generous pay increases.

“They cannot ... plead poverty, and must share their super-profits with workers who risk life and limb every day in one of the most dangerous working environments,” Cosatu said in a statement.

Some of those on strike are employed by giants such as Murray & Roberts and Grinaker LTA.—AFP