The Congress of South African Trade Unions (Cosatu) on Wednesday called on government to release its research into a possible cap on the fuel price.

In a media release, Cosatu lamented the "massive fuel price hike" of R1.34 a litre which took effect at midnight on Wednesday.

"It is becoming blatantly clear that our inept government does not have a solid plan to lessen the impact of these fuel hikes on consumers," Cosatu's parliamentary liaison said.

"The government promised a review of the fuel price structure in November 2018. Since that promised review, the public has heard nothing from the state. In the meantime, the fuel price has been increased three times with another massive increase predicted for May."

The trade union federation said the fuel price increase was an "anti-poor tax".

"While all income groups are treated equally, it is, in fact, the poor who are the hardest hit. They have to bear the brunt of not only higher transport costs to get to work and send their children to school but also have to bear the burden of higher food prices and other essential goods."

Cosatu proposed a reduction of 38 percent of the tax rate of fuel, saying government could make up for this by cutting the around 10 percent of the budget lost to corruption as reported by the Auditor General and increasing taxes for the rich.