The UNITE trade union is to ballot its members at the ESB on proposals to sell a minority stake in the company.
The Government has confirmed that it wants to sell off part of the ESB under the agreement reached on the sale of State assets with the EU and IMF.
The union disagrees, claiming that workers need to be protected.
Enterprise Minister Richard Bruton said that the Government will consider all matters before proceeding.
"Well I'm not going to tell unions what they should do," he said.
"But I think ... the Government have taken a decision, it's a prudent decision".
"There is a process in place that will make sure that the interests of the State are protected, that mistakes that may have occurred in the past in respect of sale of assets won't be made again".
"I'm confident in that process and I think workers in the ESB can be confident of that process."