The Justice Ministry ordered correctional institutions in mid-July to put an end to deceitful manufacturing-work schemes, including disguising the country of origin of products, according to documents obtained Wednesday by Kyodo News.
On July 17, the ministry ordered prisons not to accept suspicious work orders from firms and verify in writing that the jobs they accept are not illegal.
The ministry stresses in the documents that prisoners' work schemes should fall within "government policy for their correction and rehabilitation."
It was recently discovered that officials at Takamatsu Prison in Kagawa Prefecture had prisoners in 2001 falsely label more than 10,000 pairs of gloves imported from China to make them look like they were made in Japan.
The facility had accepted an order from a clothing manufacturer in the prefecture.
The prison has said, "We had no idea about having received the fraudulent work order."
"The company explained to us that we could designate products as made in Japan if they went through an additional manufacturing process in Japan after being brought in from China," claimed Shigenori Kawasaki, head of general affairs at the prison.
The sources said the labeling work was performed in a workshop by the same group of between four and six prisoners. As well as changing the country-of-origin labels, inmates had also been involved in packaging and sticking price tags on the company's products under a prison-work contract concluded in August 1998.