Fixed-mobile convergence, combined with VoIP, will allow corporate customers to slash their voice telephony bills by over a third, experts predict.

A new Analysys report warned that mobile network operators in particular will have to work hard to arrest the decline in enterprise voice revenues in the face of technology that can allow companies to bypass more expensive services.

"Companies are spending over 80 per cent of their call bill on mobile services, and that is causing them to turn to new technology for savings," said report author Margaret Hopkins.

"Wireless gateways, VoIP and Wi-Fi offer ways of cutting this bill that are independent of the network operators. Operators need to come up with innovative services to minimise the revenue leakage."

According to the study, mobile operators should launch corporate home-zone services based on femtocells to reduce the demand for dual-mode cellular/Wi-Fi phones that will take traffic and revenue away from their networks.

Analysys believes that corporate communications managers can gain most by combining corporate mobile packages with VoIP on Wi-Fi and using dual-mode phones and wireless gateways to reduce roaming bills and fixed-to-mobile charges.

The analyst firm expects that dual-mode phones will account for 14 per cent of handsets sold to enterprise customers in 2012, and that there will be four million in use in Europe at that date.