Six people were held on suspicion of counterfeiting and selling passports, foreign residency certificates, student ID cards and driving licences, according to Jiji Press and other media.

The other 23 allegedly bought the forged documents, mostly for the purpose of illegally obtaining jobs in Japan.

A Metropolitan Police spokesman said that one 29-year-old Tokyo businessman, Wang Zhichao, had been detained, but declined to confirm the other arrests.

The racket has produced about 10,000 forged official documents over 21 months and sold them to about 4,000 Chinese and other foreign nationals, the reports said.

The group has earned some 80 million yen ($1.1 billion)dollars) from what was believed to be the largest-ever forgery operation in Japan, the reports said.

In some cases, clients were solicited over the Internet and sent photos via their mobile phones.

The racket forged the documents using personal computers and delivered them the following day through parcel delivery services, the reports said.

Sophisticated anti-forgery hologram seals, attached to the documents, were made using equipment from China, the reports said. -- AFP