NAIROBI, March 27 -- African countries are expressing growing concern that emerging global rules on digital trade could limit their ability to shape the future of their economies, as negotiations continue within the World Trade Organization (WTO).

At the center of the debate is the long-standing moratorium on customs duties for electronic transmissions, a policy that prevents countries from imposing tariffs on digital products such as software, streaming services and data flows. Initially introduced to support the growth of e-commerce, the measure is now being reassessed by several developing economies, including those in Africa.

For many policymakers, the issue is no longer theoretical. Africas digital economy is expanding rapidly, dri...