National pension premiums were in arrears to the tune of a total 8.13 trillion yen for fiscal 1986 through fiscal 2002, the government said during a Cabinet meeting Friday.
The government has lost the legal right to recover the massive amount of unpaid premiums.
The Cabinet-endorsed document detailing the figures was created in answer to a request by Democratic Party of Japan lawmaker Keiichiro Asao.
Asao criticized the government for trying to increase pension burdens and decrease benefits by introducing pension reform legislation during the current Diet session, despite having long neglected to tackle the problem of unpaid national pension premiums.
The national pension law stipulates that if unpaid national pension premiums are not collected within two years, the government loses its claim over them.
The national pension program, which covers the self-employed, unemployed and salaried workers, is burdened with a massive number of defaulters, many of whom are young people without full-time jobs.
About 3.27 million people were two years in arrears with their pension premiums as of fiscal 2003.