A power cut disrupted proceedings at a briefing in Pretoria on Thursday involving possible class action against Eskom.

Lights went off at the briefing hosted by trade union Solidarity shortly before 12.30pm.

The briefing was over possible class action against Eskom over possible job losses as a result of the power crisis.

The power utility wants to increase power tariffs by 53 percent.

Earlier in the year Eskom had asked industry to conserve energy by reducing its power usage.

"The fact is that the electricity crisis is a real threat for workers. There is a high burden on workers, they could lose their jobs as a result of the crisis," said Solidarity's Dirk Herman.

Herman said that the union's four-member commission of inquiry would meet its legal counsel on Thursday afternoon to discuss the matter.

"We believe we have quite a strong case," said Herman.

Earlier on Thursday economist Mike Schussler said the crisis was affecting economic growth.

He said that the perception that South Africa had the cheapest electricity in the world was wrong.

Should Eskom be granted the hike the middle class would be hardest hit, he said.