South African construction workers have begun a strike stopping work at stadiums being built for the 2010 World Cup.

It is the biggest industrial action since new President Jacob Zuma took office in May, with around 70,000 workers set to continue their strike until employers give in to their demand for a 13 per cent pay rise.

The companies have so far refused to go beyond 10 per cent.

"It's not that we are insensitive to the 2010 projects, but that doesn't mean we have to sacrifice or compromise everything more, especially in the construction industry," said National Union of Mineworkers Deputy President Piet Matosa.

The strike action is a major challenge for President Zuma, who had to balance the demands of the union allies who helped bring him to office while keeping market-friendly policies at a time when Africa's biggest economy is in its first recession in 17 years.

The country's largest union said most of its members in the building sector had joined the protest at stadium sites and other big projects.

Officials have said the ten World Cup stadiums, half of them new, will be delivered by December.

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