The unions are demanding a 13 percent pay hike compared to the 10 percent being offered by employers. NUM has already reduced its demands from the initial 15 percent.

The move by the National Union of Mineworkers (NUM) and the Building Construction and Allied Workers’ Union comes after marathon talks collapsed last week.

A number of 2010 projects could be delayed if the strike goes ahead.

Seshoka said the e strike would go ahead until the union’s demands were met and despite any possible court interdict.

“There will be a total shutdown at construction sites, with about 70000 members of both unions expected to take part.

“We will strike until 2010 as long as the employers are not prepared to give us the 13% we are asking for. We are, of course, concerned about the possibility of deadlines for 2010 being missed, but we will not be the sacrificial lambs while companies are making huge profits,” he said.

The South African Federation of Civil Engineering Contractors (Safcec) has indicated that it intends applying for an interdict to stop the strike on the grounds that it is premature.

"In considering strike action, the union has taken into consideration the national interests surrounding 2010 Soccer World Cup stadiums and road infrastructure," the union's general secretary, Narius Moloto, said earlier this week.

FIFA’s local organising committee (LOC) chairman Irvin Khoza acknowledged that the strike would affect the completion dates and promised to engage the trade unions about the strike.

"While we acknowledge and accept and recognise the democratic right of workers to strike, there are issues we want to understand as a board," said Khoza.