According to a Reuters report analysts said that mobile operators were set for a short-term hit in revenues as many of Africa's poorer or more remote users struggle to produce the necessary documents and so risk being cut off.

A number of African governments are calling on companies to register all their pre-paid mobile phone users, who make up 97-99 percent of the market on the continent to help fight phone-related crime.

"The introduction of mandatory registration of SIM cards in at least 10 countries has resulted in a dramatic slowdown in subscriber growth and will see the disconnection of millions of unregistered subscribers," the IHS Global Insight report said.

South Africa has led implementation of the policy, giving customers until the end of this year to register numbers. Both MTN Group Ltd and Vodacom Group Ltd last year reported falls in users by 6.4 and 4.9 percent, respectively.

Drops are expected elsewhere as another nine nations, which include Kenya, Cameroon, Ivory Coast and Ghana, and account for about 80 percent of subscribers in Sub-Saharan Africa, follow suit. Deadlines range from later this month to 2011.

"As the registration deadline passes in each country, a significant one-off drop-off is expected as those unregistered SIM cards are deactivated," IHS said in the March study.