Public Enterprises Minister Pravin Gordhan presented long-awaited details of the plan to break up Eskom and open up the power sector to greater competition.

"NUM is angered with Public Enterprises Minister Pravin Gordhan's decision to go ahead with the unbundling of Eskom," the union said in a statement on Wednesday.

It made demands, including that officials abandon the plan to split Eskom and cancel power purchase agreements with independent power producers.

"If these demands are not met we will shut down electricity generation, transmission and distribution, as such plunging the country into darkness," the statement said.

The NUM, one of the largest unions at Eskom and part of the Cosatu union federation aligned with the governing party, fears the plan to split Eskom into separate units for generation, transmission and distribution will lead to Eskom being privatised.

Analysts welcomed Gordhan's plans but were sceptical that officials would follow through, given fierce opposition from unions and vested interests in the energy sector.

eCNA