South Africa’s state-owned power utility Eskom and unions have failed to reach an agreement on a wage dispute that could cut power during the World Cup after a late-night bargaining session, officials said on Friday.

“There has not been any resolution, Eskom came empty handed,” Lesiba Seshoka, spokesman for the National Union of Mineworkers (NUM), told newsmen after talks with Eskom ended late on Thursday.

The union, which represents about half of the 32,000 workers at Eskom, will hold a news conference at 11:00 a.m. local time (0900 GMT).

The NUM on Thursday was granted a certificate of non-resolution of the wage dispute, which under the country’s laws allows a union to start a strike if its members agree.

Analysts regard the threat of a strike as a union negotiating ploy to put pressure on Eskom to make greater wage and benefit concessions and do not expect the labour action to go ahead.

Eskom has said a strike would be illegal because it would threaten an essential service and that receiving permission to strike does not mean workers will put down tools.

If a strike does happen it could deal a heavy blow to manufacturing and mining companies in the world’s top platinum and fourth-largest gold producer, which could be forced to shut operations, affecting prices.

Eskom said it received a certificate for arbitration, which would compel the union to enter into talks for a negotiated settlement before being able to call a strike.

Public Enterprises Minister Barbara Hogan said there was a good possibility of reaching an agreement, local dailies reported.

In a sign the two sides may have narrowed their differences, NUM has lowered a demand for a 15 per cent wage increase to nine per cent.

Eskom has stuck to its offer made earlier this month of an eight per cent raise and a one-off payment for housing.