Builders of a stadium for the 2010 Football World Cup in South Africa were on strike Monday with talks still locked on bonuses and transport allowances, the union said.
Some 800 workers downed tools for the fifth day running at the site of the Mbombela stadium, where at least four first-round matches in the World Cup are scheduled to be played.
"They want a 2,000 rand bonus and a 900 rand transport allowance," the regional co-ordinator for the National Union of Mineworkers, Onismus Serothwane, told AFP.
Workers at the stadium in the northeastern city of Nelspruit first went on strike on November 21, however they returned to work after a day to allow their employers to come up with a suitable offer.
They resumed their strike action last Wednesday after the parties failed to find a deal.
"Negotiations will continue until an agreement can be reached," said Serothwane.
Grievances over working conditions have halted construction at other stadium building sites in Durban and Cape Town.
However, event organisers remain confident of the nation's readiness for the first football World Cup to be held on the continent.