"Quite often we find evidence that people have plugged a USB key into their computer and browsed network folders for information that they shouldn't be accessing," Klein said.

If the evidence is enough to build a case which proceeds to legal proceedings, he said companies should brief lawyers who have an understanding of ICT evidence.

"If it does go to court make sure your barrister can show what the evidence proves because at the end of the day they're the ones who have to present and argue the case in court," he said.