South Africa has lifted a freeze on bids to explore for shale gas in the central Karoo region, where energy giants hope to tap into vast underground deposits, the government announced Friday.

The country's cabinet approved the lifting of a moratorium set down last year on applications to explore for gas while a team probed the effects of controversial hydraulic fracturing drilling known as fracking.

"Cabinet endorsed recommendations of the report on the lifting of the afore-stated moratorium," said a statement, adding that a series of public consultations will be held.

The use of fracking, which blasts a mix of water, sand and chemicals into hard rock to release gas locked inside, has sparked a backlash over environmental fears of water contamination.

Anglo-Dutch energy giant Shell is among several companies wanting to explore for shale gas in the Karoo where gas finds in the 1960s were found to be technologically and economically not viable.

A study funded by the company estimated that there could be enough shale gas in the Karoo region to supply South Africa with energy for 400 years, at current rates of consumption.