The hike in the price of petrol of 23 cents a litre, which comes into effect at midnight on Tuesday night, will bring the price to its highest since 2008 and is bad news for both vehicle owners and consumers.
Transport businesses and commuters said it would hit them hard.
Economist Sid Singwane said: "The ripple effect of the hike will hit consumers hard by the end of the year, when food and commodity prices go up."
He said the poorest of the poor would suffer as the price of food and other day-to-day items would increase.
"Illuminating paraffin, a common feature in thousands of homes in townships and informal settlements around Gauteng, will rise by 41c a litre wholesale, and this will impact on their transportation and basic food costs," Singwane said.
The retail price of all grades of petrol will rise by 23c a litre and diesel will increase by 36c. The price hike means inland drivers will pay R10.77 for petrol, and diesel will rise to R10.01 a litre.
Tuesday night's increase follows an 18c hike in April and one of 29c in May, and is partly due to the weakening rand against the dollar, the Department of Energy said.
"It is certainly bad news all round," the Automobile Association's Gary Ronald said.
He said the increase would have a negative effect on South Africans, the biggest one being less money in people's pockets.
"In addition to increases in public transport, consumers will see food on shop shelves increase in about a month's time, when all food consumables get affected."
The South African National Taxi Council has said it would have to increase taxi fares around mid-November. They said they had no choice, given the hike.
"When we heard the news, my wife and I counted the costs and discovered that it could push our petrol cost up to R3 000," Masi Magus, who lives in Pretoria West and works in Joburg, said.
Some people said they would form lift clubs.
"We will pool together when coming into work from Centurion," Zandi Magagula said. "There are so any of us who come into town that we will make great savings if we travel together."