Three of the 17 ministers in Prime Minister Junichiro Koizumi's Cabinet said Friday they have not paid their premiums for the compulsory National Pension System.

Ongoing Diet deliberations of contentious government-sponsored pension reform bills ground to a temporary halt following the revelations, and the Democratic Party of Japan demanded that the three -- trade minister Shoichi Nakagawa, home affairs minister Taro Aso and Defense Agency chief Shigeru Ishiba -- be summoned to the session for questioning.

Nakagawa has not paid the premium since it became mandatory to do so in April 1986. Aso said he did not pay his premiums between November 1996 and September 2000, and Ishiba said he has not made a payment since October 2002.