Some life insurance companies, including industry leader Nippon Life Insurance Co., have found they hold policy contracts apparently signed without the knowledge of the purported policyholders and others bearing the names of fictitious customers, informed sources said Monday.

The revelations came in the process of internal investigations by the insurance firms into their recently discovered failures to pay insurance money to which the policyholders are entitled, the sources said.

The signing of contracts without policyholder consent likely constitutes a violation of the Insurance Business Law, and the Financial Services Agency intends to take disciplinary action after getting to the bottom of the matter, officials with the financial watchdog said.

The irregularities came to light when the life insurers tried to contact customers whose contracts were canceled due to stalled premium payments. Some of those contacted said they had never taken out any insurance, even though their names were on the companies' contracts, according to the sources.

Some insurers were unable to locate the policyholders and some policyholders said they signed on at the request of insurance salespeople but have never paid any premiums, the sources added.

The findings suggest that sales staff, under pressure to fill quotas, might have filled out policies themselves using fictitious customer names.

Not all of the suspected contracts were necessarily made out unlawfully. Some policyholders might have actually signed the contracts but are now difficult to locate, the sources added.

Similar incidents were discovered in the past among nonlife insurers.

In February 2006, for example, Sompo Japan Insurance Inc. admitted that some of its salespeople had paid premiums on policies made out to friends and relatives. As a penalty, the FSA ordered the company to temporarily suspend some of its operations.

Meiji Yasuda Life Insurance Co. was found to hold dozens of illegally signed contracts.