The workers staged their latest one-day strike on Wednesday over allowances and bonuses.

The Medupi plant’s first unit was due to be completed in 2012 but will now open in June, although the whole station will not be operating at full capacity of 4,764-megawatts until 2020.

The station, which will be the fourth largest coal plant in the southern hemisphere, is expected to ease South Africa’s power crisis, which regularly leaves factories, shops and homes in darkness and has hit economic growth.

“Over a thousand workers have been fired,” Eskom spokesman Khulu Phasiwe told AFP. “Many of these workers had participated in an illegal strike.”

The National Union of Metalworkers of South Africa (NUMSA) said they were dismissed via phone text messages.

The sacked workers were employed by contractors building the station, located in northeast South Africa.

One of the contractors, France’s Alstom, told AFP that none of its workers had been sacked.

South Africa’s ageing coal-fired plants struggle to provide the 30,000 megawatts of electricity consumed each day in Africa’s most advanced country.

With public anger growing over the power cuts, the government this week fired several executives at Eskom.

“Whatever is happening, there’s a problem,” President Jacob Zuma told public broadcaster SABC on Thursday night.

“Why is Medupi not finishing, it should have finished more than a year ago?”