South Africa's state-owned power utility says that following an illegal strike about 1,000 construction workers have been fired, halting work at an already delayed but much needed power plant.

Eskom spokesman Khulu Phasiwe said Friday that more workers may be dismissed. The workers, employed by contractors, were building the Medupi power plant, one of three new power plants expected to end rolling blackouts in South Africa.

Phasiwe says 3,000 workers took part in an illegal strike on Wednesday. According to a statement by the National Union of Metalworkers of South Africa, the workers were demanding bonuses and an end to layoffs.

Eskom previously said they expect Medupi to be fully functional by 2017. Phasiwe said the plant will now only be completed by 2020, provided there are no more delays.