Johannesburg - Cosatu must lead a campaign against Eskom's proposed electricity tariff hikes, the SA Municipal Workers' Union (Samwu) said on Wednesday.
"Cosatu and its unions must ensure that it forces government to immediately halt the unaffordable increases Eskom is demanding," spokesperson Tahir Sema said in a statement.
"We call on [the] Congress of SA Trade Unions [Cosatu] to lead a campaign against Eskom, similar to the highly successful mass action we led against the e-tolls."
Eskom has applied for a 16% increase in electricity prices each year for the next five years.
This would take the price of electricity from 61 cents a kilowatt hour in 2012/13 to 128 cents a kWh in 2017/18, more than doubling the price over five years.
Sema said the working class could not afford this increase.
"The poor cannot afford any more increases; these increases have a devastating impact on the lives of the working class and poor."
The government should consider alternative ways of funding Eskom, he said.
Samwu wanted a high-level task team to be set up as soon as possible to discuss alternative forms of funding.
It should include senior government officials, politicians and civil society.
Sema said irresponsible increases in basic services could cause mass instability and put undue pressure on the economy.
Eskom submitted its application for the increases to the National Energy Regulator of SA (Nersa) on Friday.
Nersa will announce its final decision in February, following an extended period of consultation and public hearings.
The new tariffs would apply from April next year.