With security threats a major concern to companies thinking of switching to VoIP communications systems, there has emerged a group of companies aiming to expose these problems and help find solutions.

One such company highlighted by Computer Weekly is Sipera Systems which was set up in 2003 to look specifically at VoIP networks and probe for vulnerabilities.

The firm can then pass on this information either onto the users or to manufacturers who can work to fix the security flaws.

A recent announcement by the Sipera Studios Viper Lab exposed seven vulnerabilities in SIP-based softphones and instant messaging services like AOL Messenger and Windows Live Messenger.

"Viper Lab looks only at VoIP and unified communications," said Brendan Ziolo, marketing director of the analyst firm.

"By proactively seeking out vulnerabilities, we are protecting VoIP systems against these attacks before they can even happen."

While companies are usually very concerned about ensuring the security of their computer network, they may use consumer VoIP clients to take advantage of VoIP on the cheap.

But Mr Ziolo said firms should have the same high security standards for VoIP and treat it separately.

"It's important to understand that VoIP is now an application on the internet and has its own security needs," he said.

"Enterprises should also realise that it is challenging and requires lots of time and work to have a secure VoIP network - but it's not impossible."