JOHANNESBURG—U.S. oil giant Chevron Corp. CVX -0.08%has joined the hunt for natural gas in South Africa, whose untapped shale prospects have already attracted attention from Royal Dutch Shell RDSB.LN -0.11%PLC, but also raised the ire of environmental groups.

Estimated to hold the world's fifth-largest shale gas reserves, South Africa hopes investment in its energy sector will create much-needed jobs and help maintain cheap power for its mining heartland. But some locals are concerned about the impact of hydraulic fracturing in the Karoo, an isolated and region that is rich in nature.

Chevron, whose African portfolio is among the most diverse and long-established among major U.S. oil companies, said it would partner Toronto-listed minnow Falcon Oil & Gas Ltd. FO.V -2.33%one of only three firms with permission to conduct seismic studies of the local geology.

The five-year partnership will also allow Chevron to team up with Falcon should it exercise an exclusive right to convert the permit into a drilling license.

The move comes only three months after South Africa lifted a temporary ban on shale gas exploration, imposed early last year in response to concerns the controversial hydraulic fracturing technique, widely known as fracking. Environmental groups and some locals fear fracking risks permanently damaging the Karoo, a region know for its arid beauty but also its poverty.

Proponents counter that fracking the Karoo could provide both jobs and development, two of South Africa's most urgent and politically charged needs.

A study by local think-tank Econometrix, which was paid for by Shell, said that even if only a 10th of the 485 trillion cubic feet of gas that the U.S. Energy Information Administration believes the region contains was extracted, it would still lead to the creation of thousands of jobs and provide 400 years of power in a country that still imports 60% of its energy needs.

Shale gas and oil in the U.S. has transformed the North American energy market and beyond, raising alarm bells among some members of the Organization of the Petroleum Exporting Countries who say the group may eventually need to rein in output to avoid glutting the market as U.S. oil production surges.

Still, companies say production elsewhere could be years away. Shell has said it would need to spend around $200 million to drill six wells for the first stage of exploration and that moving the Karoo to production would take about 10 years.

Chevron declined to comment beyond its earlier statement about the partnership with Falcon, to which it will pay $1 million to cover upfront costs.

The fracking issue is divisive in a country still wrestling with the economic and political legacy of apartheid. Some have noted that the environmental groups that oppose local fracking tend to attract more white members, including local landowners, who tend to be better off than black workers, or some who live in urban areas unlikely to be affected by the exploration.

"The main bodies that oppose fracking represent themselves as environmentalists, but their membership is overwhelmingly white, moneyed landowners," said Noor Kapdi, a Cape Town lawyer and a director at the South African Oil and Gas Alliance, an industry lobby group.

By contrast, a body representing the region's mostly poor black community have given a tentative welcome to fracking.

The Karoo Shale Gas Community Forum, a coalition of small farmers, unions and church groups in the region, has said it would like to know more about the planned project and what they could do to help bring jobs to the region.

Some environmental groups say they plan further action to block exploration attempts.

One such group, Treasure the Karoo, has said it would lodge an appeal with the Department of Mineral Resources if fracking is permitted or if exploration licenses are awarded.

Another complication arose in May—South Africa will site a radio telescope in the same area where Shell wants to undertake fracking operations. The project requires that industrial activity be located miles away for the telescope to work.