Former top education ministry bureaucrat Kihei Maekawa reaffirmed on Monday his assertion that top officials in the government manipulated key decision-making processes to help out a school run by a close confidant of Prime Minister Shinzo Abe.

"I believe there was some behind-the-scenes work at play on the part of Prime Minister's office," Maekawa told a one-off committee session in the Diet held to deliberate the issue. He remained adamant that the alleged intervention was characterized by "unfairness" and "opacity."

In May, Maekawa rocked Japan's political arena by vouching for the authenticity of leaked internal documents that pointed to alleged favoritism on the part of Abe.