A South African advocacy group called for a moratorium on hydraulic fracturing operations for natural gas despite support from President Jacob Zuma.

The government banned hydraulic fracturing, known also as fracking, in 2011 but lifted the moratorium in October after releasing new regulations that govern shale operations. The U.S. Energy Information Administration estimates South Africa holds 390 trillion cubic feet of recoverable shale gas resources.

Zuma in his State of the Nation address in February said shale natural gas could be a "game changer" for the South African economy.

Jonathan Deal, chief executive officer at Treasure Karoo Action Group, said his organization is calling for a reinstatement of the ban.

"We have taken serious note of the promises of President Zuma to South Africa in connection with fracking and are now poised to take legal steps," he said in a statement Tuesday.

Some of the chemicals used in fracking fluid are viewed as a threat to groundwater supplies. While many countries are working to replicate the U.S. success with shale, several others have opted to ban the controversial drilling practice as a precaution.

So far, international energy companies are still waiting for licenses for shale gas exploration.