The National Police Agency said Friday it has received 17 reports since late December of online fraud known as "phishing."
The people operating the scams typically send e-mail messages that appear to come from legitimate companies, and ask recipients to enter personal information such as credit card numbers and Internet banking passwords on fraudulent Web sites.
Of the 17 cases reported to a hotline the NPA established on Dec. 24, none of the people involved lost money because police contacted the companies whose names were used in the scam and shut down the fake Web sites.
There have been increasing reports of damage from phishing in Europe and the U.S.
The NPA confirmed Japan's first case of phishing late last year. It did not release details but the damage is believed to have amounted to several hundred thousand yen.
On Friday, the NPA hosted a conference in Tokyo to study countermeasures.