The report appraises recoverable gas resources in the nation at 36 trillion cubic feet, which is in stark contrast to earlier unrisked estimates from the Energy Information Administration for the Karoo Basin of up to 485Tcf.

South Africa's Department of Mineral Resources told the nation's parliamentarians that there was a high degree of uncertainty about South Africa's potential given there had been so little drilling focused on the shale formations.

The uncertainty is a lesson Europe learned well in recent years with high profile disappointments in Poland and Denmark, and South Africa can only discover its potential once it finalises regulations for shale gas exploration.

The government says South Africa may not know the size of any potential shale gas resources for 3-10 years.

South Africa has potentially vast but unquantified shale gas resources in the Karoo Basin but has lost several years of exploration lead time to government assessments of the safety of shale gas exploration and extraction, despite the fact the nation is in a state of energy emergency.

Econometrix, the nation's largest independent macro-economic consultancy, estimated in 2012 that 50 trillion cubic feet shale gas resources could add more than $20 billion to South Africa's annual gross domestic product and create 700,000 sustainable jobs - providing a solution to power supply challenges and ensuring southern Africa's energy security.

A high level overview of the world's most promising shale plays by the US Energy Information Administration estimated the nation risked shale gas potential of 370Tcf in technically recoverable resources.

The DMR has received five exploration applications in recent years but all have stalled as the nation attempts to establish regulations for unconventional exploration.

Of course, the full extent of the viability of the shale plays will only be known if and when the shackles are taken off shale exploration.

If the licences are granted, the applicants will kick off exploration with desktop studies and seismic surveys.

The most promising shale areas are controlled by just three groups: Shell; Ireland-based Falcon Oil & Gas; and Australian junior Challenger Energy. Chevron Corporation was in the mix with Falcon, but pulled out following the fall in oil prices and disappointment in its European shale investments.

Challenger, which is partnered with local firm Bundu Gas & Oil Exploration, secured its permit several years ago around a promising 1968 gas discovery that flowed gas to surface from a vertical unstimulated well.

Several wells around the CR 1/68 discovery indicated thick, uniform shale sections in the Ecca Shales below 1500m.

The EIA assessment only considered the basal Ecca Shales because of the high level of total organic content, but Challenger believes the shallow zones also have good potential because the flow recorded in the late 1960s came from the Upper Ecca.

Challenger says while the EIA study assessed potential within its application area of 7Tcf, it can see further upside.

South Africa's Portfolio Committee on Mineral Resources has expressed a desire to complete further reports on fraccing and the relevant legislation before unconventional operations can proceed.

The policy is expected to be finalised soon, with permit awards expected later this year.