Cape Town - A rise in the petrol price of 29c per litre for 93 octane and 28c for 95 octane from Wednesday comes at a particularly bad time, trade union Uasa said on Monday.
Spokesperson Andre Venter said the increase represented a huge setback for South African workers.
"Not only have we just left the expensive festive season behind us, but parents of school-going children will have the extra expense of school gear and rising school fees to reckon with."
Venter said gradual signs of economic recovery in the third quarter of last year and the benefits of festive season spending could be neutralised by the price increase.
Most South Africans were still struggling to shake the effects of the world-wide recession.
The petrol price rise represented yet another financial blow for them.
"We will no doubt experience another ripple effect on production prices, causing consumers to pay more for goods at the counter, while the higher price will probably also contribute to a steeper inflation rate," Venter said in a statement.