Protesters started arriving at Mary Fitzgerald Square in Johannesburg before 9am on Friday ahead of a march to show their rejection of plans for tolled roads in Gauteng.
A few early arrivals danced to music being played from a sound system on a flat bed truck while shop stewards from the massive union federation gathered for last minute meetings.
Marchers there are expected to start gathering from around 9.30am and traffic officials have warned of road closures.
Metro police spokesman Chief Superintendent Wayne Minnaar said the marchers were expected to proceed to Gauteng premier Nomvula Mokonyane's office in Simmonds Street, the transport department in Pritchard Street, and the housing department in Sauer Street, to hand over memorandums.
A similar march is set for Tshwane. Workers would gather at the corner of Sophie de Bruyn and Johannes Ramokhoase streets in Pretoria.
The group would go to the transport and finance departments to hand over memorandums against e-tolling in Gauteng, City of Tshwane spokesman Console Tleane said.
The protest was expected to finish at the City Hall there around 2pm.
The Opposition for Urban Tolling Alliance (Outa) called on all participants in the protest marches to refrain from violence and damage to property.
"Outa ... trusts these will be conducted in a most peaceful manner to demonstrate society's respect for property rights and the law," said Outa chairman Wayne Duvenage.
"We share BUSA's concerns and call on all participating in protest action to be responsible and refrain from any violence and damage to property," said Duvenage, referring to a similar call by Business Unity SA.
The High Court in Pretoria on Wednesday reserved judgment on the future of the e-toll system following a challenge by Outa.
Like Outa, Cosatu want e-tolls scrapped, saying workers cannot afford it and government must prioritise efficient affordable public transport.
Cosatu secretary general Zwelinzima Vavi called on other provinces to join the opposition to Gauteng tolls.
Government spokesman Thabo Masebe also called on protesters to abide by the law. "Government calls on marchers to exercise their right to protest within the ambit of the law," he said.
Earlier this week Cosatu provincial secretary Dumisani Dakile had threatened that the union federation's members would demolish the toll gantries if the government did not scrap the system.
Speaking to EyeWitness News on Thursday morning Dakile however said what he had meant was that government officials who tore down houses in Lenasia should also tear down the gantries.
Vavi said Friday's protest was just the beginning, with another protest planned for December 6.