Mozambique's mobile firm Vodacom which oversees the money transfer platform, M-Pesa, says it blocks around 2,500 numbers a month linked to fraud.

Some 80 people are swindled everyday in fraudulent mobile money transactions, according to Vodacom.

Vodafone M-Pesa's head of marketing, Daisy Madeira, said numbers from other mobile service operators were also involved in the fraud and called for joint efforts.

"If there were synergies between all mobile phone operators, it would help customers a lot, for example, if a number is linked to fraud by one operator, it is blocked on the other side," Ms Madeira said.

Another telecommunications firm, Movitel, says they have managed to stop fraudulent transactions before completion - even though it has been receiving complaints from its customers.

The Mozambican Communications Regulatory Authority says biometric registration is the solution.

It says there is need for registration and setting up of equipment that can monitor telephone interactions.