Four more Cabinet ministers, including Chief Cabinet secretary Yasuo Fukuda, and opposition leader Naoto Kan said Wednesday they failed to pay mandatory premiums for the basic pension system.

Financial Services Minister Heizo Takenaka, Finance Minister Sadakazu Tanigaki and Toshimitsu Motegi, minister in charge of the information industry and issues related to Okinawa and Hokkaido, also admitted they had not paid.

Last week, three Cabinet ministers -- trade minister Shoichi Nakagawa, home affairs minister Taro Aso and Defense Agency chief Shigeru Ishiba -- said they had not paid the obligatory premiums.