THE National Union of Metalworkers of SA will go to court over its right to picket outside the National Energy Regulator of SA offices, the union's general secretary said yesterday.

"It will either be Monday or Tuesday," Irvin Jim said. He said the legal papers were still being drafted.

Numsa planned to picket outside Nersa's offices in Arcadia in Pretoria for 18 hours from 6pm on Wednesday.

"The picket outside Nersa offices is part of Numsa's campaign against Eskom's application for a 16% average annual increase between 2013 and 2018."

Jim said the picket would include an all-night candlelight vigil on Wednesday evening and protest action on Thursday morning when the regulator would announce whether it granted the increase.

Jim said for the past two weeks Numsa has been negotiating without success with the SA Police Service and the City of Tshwane metropolitan police to grant the union a permit to protest outside Nersa offices.

He said considerations about the protest taking place both during the day and the night - as well as apartheid-era legislation that defined Nersa offices as a protected "key point" - appeared to be behind the delay.

With the picketing the union aimed to make its demands clear.

It said Eskom should be given an inflation-related increase implemented over three years. The next three years must be used to come up with an alternative model for funding electricity generation.

"With all the evidence presented on how disastrous the electricity price hikes will be, as Numsa, we call on Nersa regulators . [to] think of workers, poor people and the country as a whole."