Restricted competition has helped push up charges, according to research by the Overseas Development Institute (ODI).
Money transfer company Western Union said that fees were set according to factors such as local taxes.
The company “delivered much-needed services to individuals”, it added.
The research found that average fees of 12% to send $200 (£119) were twice the global average.
Siddo Deva of Comic Relief said: “Imposing such high remittance fees from hard-earned income is hurting the African diaspora and, more importantly, their families and communities in the countries of origin.”
Fees charged to Africans wishing to send money back amount to a “super-tax” that could be better spent on education or health, ODI said.
“Africans living abroad make huge sacrifices to support their families, yet face charges which are indefensible in an age of mobile banking and internet transfers,” said Kevin Watkins, the report’s co-author and ODI Director.
Reducing charges to a 5% global target for 2014 set by the G20 would cut fees by $1.8bn (£1.08bn), the ODI said.
It added that two companies dominate the money transfer market in the region, restricting competition.
Western Union and Moneygram account for about two-thirds of remittance payout locations in Africa.
“Global markets are dominated by an oligopoly of money transfer operators (MTOs) and regional markets by a duopoly,” the report said.
In addition, there is a lack of transparency over commercial agreements between MTOs and banks, and regulatory practices that restrict market entry, ODI added.
Carl Scheible, Moneygram’s executive vice president of UK and Africa operations, told the BBC World Service that the ODI figures were not representative.
“We do not recognise these numbers as they are,” he said.
Moneygram charges depend on how much money is being sent. Mr Scheible said that most people send money to Africa in amounts of about £200, which have a lower fee.
When taken as a whole, the average percentage that Moneygram takes for money transfers to Africa from the UK is 5.1%, compared with a global average take of 4.9%, he said.
In addition, prices have been coming down “quite dramatically” over the last decade because of digitisation.
However, costs to the business still include logistics and cash handling. “Cash has to be delivered, has to be picked up – we’re talking armoured cars,” Mr Sheible said.
“The reality is we are providing a very competitive service, a fairly priced service, based on speed, reliability, security of the money arriving.”
Western Union said that it had “delivered much-needed services to individuals looking for fast, convenient and reliable ways to send money to family and friends” during 20 years of operations in Africa.
“Our pricing varies between countries depending on a number of factors such as consumer protection costs, local remittance taxes, market distribution, regulatory structure, volume, currency volatility, and other market efficiencies,” it added.
“These factors can impact the fees and foreign exchange rates offered by corridor and service type.”
( Courtesy BBC & Overseas Development Institute ….. Source …… New Africa Business News )