According to a GSMA report The Mobile Economy Africa 2016 revenue growth rates for African mobile companies - which topped 3.8% at 53.5 billion in 2015 - will slow down in the next five years, highlighting the need for telcos in the region to cultivate other revenue streams.

Although there has been a marked increase in the uptake of data-enabled platforms such as social media and instant messaging applications, African mobile companies still have to focus on voice and SMS.

Mobile operators in Africa have "consistently reported double-digit data revenue growth" over the last five years, the GSMA says. "Although the use of IP-based services supports data revenue growth, the increasing pressure on traditional voice and SMS revenues will continue to weigh on overall revenue growth."

Most telcos in Africa also face the risk of large proportions of consumers in the region being in the lowest tier of the income pyramid.

Other executives at mobile companies in Africa have responded to the projected decline in revenue from voice by cutting tariffs, with Safaricom saying this week it has reduced international roaming tariffs.

This would be worsened by a "weak economic outlook" that is set to persist and this is seen increasing "the risk of spending cutbacks by hard-pressed consumers" who will now more likely take advantage of prepay services.

Douglas Mboweni, CEO of Econet Wireless, said this month that the company is balancing promotions – which others feel are tariff reductions – and prospects for profitability. He said the promotions were favourable for consumers and added that they would promote network usage.

"Mobile companies are having to cut tariffs to survive and grow revenues. There has also been greater emphasis on bundles for data platforms because that area is now taking greater focus as consumers shift from voice to cheaper data to manage costs," said a consultant engineer with one of Zimbabwe's mobile companies.

The report adds that mobile companies in South Africa, Nigeria and Egypt have also spoken out about rising costs. Adding to the cost pressures have also been currency depreciation in the region, with currencies in SA, Nigeria and others having taken knocks.