* Parties hope to conclude agreement on Tuesday
* NUM says to consult members before ending strike
* Strike threatens World Cup stadiums
(Adds detail, quotes, background)
By Muchena Zigomo
JOHANNESBURG, July 9 (Reuters) - South Africa's National Union of Mineworkers and employers said on Thursday they had agreed a plan for better wages which could end a strike threatening to delay work on stadiums for the 2010 World Cup.
"After intense negotiations...a framework of an agreement which contains an improved offer has been established," the union and employers said in a joint statement.
"Both parties commit to persuading their members of the acceptability of the framework and will endeavour to conclude an agreement by Tuesday."
Lesiba Seshoka, spokesman for the NUM, which also represents workers in the building sector, said the union would only decide on ending the strike after consulting its members.
"They can decide not to accept the offer, and if they decide not to accept it (the strike) is not over," he told Reuters.
Seshoka earlier said employers had offered a 10.4 percent pay rise, while the union was holding out for 13 percent.
The pay strike, which started on Wednesday, has stopped work at stadiums for the World Cup.
It has also halted work on the mass transit Gautrain high-speed rail project, 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 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.
The increasingly vocal trade unions pose a challenge for Zuma, who has to balance union demands to help the poor with market friendly policies that have helped South Africa gain investor confidence.
Workers in various sectors have demanded substantial wage increases as living conditions become tougher because of South Africa's first recession in 17 years.
Firms that could be affected by the dispute include Murray & Roberts Holdings Ltd, WBHO and Group Five.
(Reporting by Muchena Zigomo; editing by Michael Roddy)