ANC Youth League acting president Ronald Lamola slammed e-tolling in an address to protesters in Johannesburg on Friday.
"It's a sophisticated way of taking from the poor," said Lamola as Congress of SA Trade Unions members and supporters gathered in the CBD to show their opposition to government's plans to toll Gauteng freeways.
"We must stand still by not buying e-tolls. This thing must collapse," he said.
"In 20 years it will be very expensive. It will be an expensive future for South Africa," said Lamola.
He said the march was to "combine black and white" and was for all South Africans.
Meanwhile, in Pretoria, protesters handed a memorandum to National Treasury official Huntly Pringle, to voice their opposition to the e-tolling plans.
Pringle, a director in Director-General Lungisa Fuzile's office, said they intended to consider it in "grave detail".
"We will do our very best to make sure you get a response by Monday."
People at nearby sidewalk cafes stood up and danced as the throng moved past them, and pedestrians randomly joined the march.