Former Prime Minister Naoto Kan called Tuesday for the full disclosure of testimony regarding the Fukushima nuclear crisis, including that of plant chief Masao Yoshida.
Kan, prime minister during the March 2011 disaster, welcomed the Abe administration's decision to release Yoshida's testimony in September.
"It is the most important material to understand the cause of the accident and how it developed," he said.
Kan, known for his opposition to nuclear power, is currently visiting Australia at the invitation of an environmental group.
"It is necessary to re-examine all the facts" related to the nuclear crisis, he said.
The government had resisted releasing Yoshida's testimony. Before he died of esophageal cancer in July 2013 at age 58, he signed a statement preventing the release of interviews, citing concerns that he would be misinterpreted.
Yoshida was interviewed for more than 20 hours from July to November 2011 by a government panel examining the crisis.
The government is also preparing to disclose testimony by others involved in the disaster as soon as it obtains consent from the interviewees.
"Since public interest of the examination of the accident is extremely high, I believe testimony by then senior executives of Tokyo Electric, including the chairman and president, as well as records of its teleconferences, should be disclosed," Kan said.
He said he has approved the release of his own testimony.