There has been endless discussion at this year's Mobile World Congress about new business opportunities for telcos; specifically, expansion into new verticals and providing different types of services. But one company points out that the quest for fresh revenue streams also brings with it a set of new challenges around fraud and revenue assurance.

In the machine-to-machine space – smart metering, connected cars and the like - operators are dealing with a much more complex value chain than they are used to, João Resende, VP of product development at Portugal's WeDo Technologies, explained to Total Telecom in Barcelona this week.

"Many times there are many partners," Resende said. And with so many parties involved, operators need to be sure they are charging the right amount to the right companies to protect their margins.

"The business model changes," he said.

In addition to revenue assurance, operators also need to be aware of the possibility for fraud once they have stepped out of their comfort zone of providing traditional calls, messaging and data services to customers.

"They might be missing risks they are not used to coping with," Resende warned.

The move to mobile financial services means that operators are now responsible for transmitting information that is worth a lot more than a voice call or text message. It's not a call anymore, "it's €500," Resende said.

"This is a new reality for mobile operators," he added. "[They need to] make sure there is no leakage."

There are also issues like "brand and consumer confidence" to take into account, he said.

And operators that are already established in the mobile money space are well aware of this.

"The next big opportunity for us is in mobile banking," said Millicom CEO Hans-Holger Albrecht, in a keynote address.

People can already send money between countries, including the currency exchange element, he explained. Other services, such as insurance will follow.

"You're dealing with people's money," Albrecht said. "It's all about trust."