Ngubane was being interviewed by news agency Reuters on the sidelines of the World Economic Forum on Africa, held in Durban, last week, when he said that the plan was not "set in stone" and "could be shelved depending on economic growth and other factors".
Despite this, the National Union of Mineworkers has reiterated its position that the Eskom board must reverse the decision to close down these five power stations.
The National Union of Mineworkers states it is going to defend jobs for its members and will declare a national strike if Eskom decides to decommission the five power stations.
The union states it is not enough for Eskom board chairperson to say the decision to close down the five coal-fired power stations was not set in stone. Its members want the board to totally reverse the decision as closure will lead to massive retrenchments.