Norwich Union (NU) is suing 28 people after uncovering an alleged £1.5m fraud involving a member of its staff.
Carol Birrell from the Southend-on-Sea office is named as the only NU employee involved.
It is believed that she was inflating claims and keeping the excess cash over a period of ten years. NU froze her assets after discovering money had disappeared. She was suspended from her job and then dismissed.
An NU spokesman said: "We decided to act because we needed to freeze her assets in order to get the money back. No policyholders' money is at risk."
The defendants were named in a High Court writ. Most are from the Liverpool area, where Birrell has a home. The case is being investigated by Merseyside Police.
NU is investigating how the deception happened and plans to use the findings to tighten security.