Johannesburg - Disgruntled workers at electricity parastatal Eskom may adopt "radical measures" that will have "far-reaching" implications, the National Union of Metalworkers of SA (Numsa) said on Monday.

This followed what the union called "protracted wage and conditions of employment negotiations with the intransigent Eskom management over the past couple of months".

According to Numsa's statement, the union had demanded an increase of 14% for Eskom workers while Eskom had offered an increase of 8%.

"Numsa believes that Eskom has a moral responsibility to concede and adhere to the demands of workers... the failure by Eskom to adhere to these demands will leave the workers with no other option, but to adopt radical measures," the statement said.

Numsa said the measures may include the unleashing of a blackout "if need be".

It added that it did not want to reach this point, "although Eskom is pushing us in that direction".

Numsa said the call to consider "radical measures" should not be misinterpreted as "anti-Zuma administration or ANC".

"This is the only mobilisation tool and power which workers can use to advance their demands of decent work and better conditions of employment."

Eskom spokesperson Fani Zulu said the parastatal and Numsa were in talks at the Commission for Conciliation, Mediation and Arbitration (CCMA).

"There were talks on July 28 and 29 and we are going back to the CCMA on August 5," Zulu said.

He said that both the union and Eskom had "moved" when it came to wage agreements.

"Eskom has gone beyond the 8%," he said.

- Sapa