Tokyo police say a suspected Japanese phone scam group may have rotated its members and moved its base around in Cambodia to evade detection by authorities.

The police arrested 19 Japanese nationals on Tuesday on suspicion of running phone scams targeting people in Japan from a hotel in Cambodia. They were deported from Cambodia to Japan on the day.

The suspects, including 38-year-old Okamoto Hiroki, are aged from 25 to 55 years old.

The group is believed to have swindled about 250,000 yen, or about 1,900 dollars, in electronic money from a Tokyo resident in her 60s in January.

The police have not disclosed whether the suspects have admitted to the allegation.

The 19 are all believed to be "foot-soldiers" in the group's fraud operations, making calls to potential victims in the hope of stealing money from them.

The group used a hotel in the southern Cambodian city of Sihanoukville as a base.

Inside their rooms at the hotel, investigators have found lists of the names and phone numbers of victims for about 70 other phone fraud cases.

Tokyo police believe that the 19 were also involved in those cases, which have been reported since last April.

The police have also found that some of the suspects had stayed at the hotel since late December.

They say the 19 suspects had arrived in Cambodia separately since November 2021. At least one of them arrived in Cambodia in January this year.

Investigators think the scam group may have changed its members and moved its bases in Cambodia to evade police crackdown, while continuing with its crimes.