The practice of using the Cabinet secretariat's discretionary funds for "Diet affairs" -- buying off both ruling camp and opposition lawmakers to ensure important legislation gets passed smoothly -- dates back decades, according to Upper House member Sadao Hirano.

Deputy secretary general of the Liberal Party, Hirano said he was a "conveyer of the secret funds" when he worked for top Diet leaders in the 1960s and 1970s.

In an interview with The Japan Times, Hirano said that as secretary to Lower House Speaker Shigesaburo Maeo between 1973 and 1977 and to Vice Lower House Speaker Sunao Sonoda from 1965 to 1967, he would go to the Prime Minister's Official Residence to receive money for political scheming.