* Union says employers have improved wage offer
* Employers group says workers should curb demands
By Alison Raymond
JOHANNESBURG, July 9 (Reuters) - South Africa's National Union of Mineworkers expects a deal will be reached on Thursday or Friday to end a strike which threatens to delay work on stadiums for the 2010 World Cup, a spokesman said.
Lesiba Seshoka told 702 Radio that employers had come to talks with a changed attitude and were prepared to improve a pay offer of 10.4 percent. The union has been demanding 13 percent.
"We have the confidence that we should be able to either today or tomorrow reach a resolution to the dispute," Seshoka said. There was no immediate comment from employers.
The pay strike since Wednesday has halted work at stadiums for the World Cup and poses a challenge for President Jacob Zuma, who has little room to meet the demands of union allies flexing their muscles since he took office in May.
The South African Chamber of Commerce and Industry said workers should curb their demands.
"The South African economy is not immune to the global downturn and unrealistic demands on business will only serve to exacerbate the situation and retard economic recovery," it said in a statement.
Workers in various sectors have demanded double-digit wage increases as living conditions become tougher because of South Africa's first recession in 17 years.
The increasing voice of trade unions is a challenge for Zuma, who has to balance union demands for pro-poor policies with market friendly policies that have helped South Africa gain investor confidence.
The NUM has said 70,000 workers are affected by its strike. Only its construction workers have been on strike so far, however, and there has been no impact on mining in South Africa, the world's top producer of platinum and a big gold miner.
Firms that could be affected by the dispute include Murray & Roberts Holdings Ltd, WBHO and Group Five. (Additional reporting by Phumza Macanda, Editing by Matthew Tostevin)