Prime Minister Shinzo Abe revealed Friday that he was aware of problems with the nation's pension premium payments by late last year, long before the government acted at the end of May.

Revelations that the Social Insurance Agency mishandled 50 million pension premium records has not only outraged the public but also put Abe in a difficult spot ahead of the July 29 House of Councilors election.

"I realized there were problems with the pension records between the end of last year and early this year," Abe told a group of journalists.