Former Japanese Science Minister Yoshiaki Takaki reportedly interacted with senior members of the government and ministry officials and decided not to release the public data of the national System for Prediction of Environmental Emergency Dose Information (SPEEDI), according to leaked internal documents.
Predictions on the amount of radiation that had already been released from the crippled reactors, as well as further radiation that might escape into the atmosphere "could by no means be released to the public," the Kyodo News quoted the document, as saying.
The document, which is dated March 19, had also predicted that clouds of radioactivity could be released from the plant and spread across northern and central Japan, including Tokyo.
An independent panel report has also revealed that government was drawing up plans to evacuate 13 million Tokyo resident and also reassuring the public that there was no reason to worry about the situation at the nuclear facility.
The SPEEDI report provided a worst-case scenario in which all four damaged reactors at the plant exploded, triggering explosions at nearby nuclear facilities, The Telegraph reports.
The Japanese ministry decided that the SPEEDI data should not be released but that "more general" information could be prepared for the public.
The latest revelations are likely to increase distrust in the Japanese authorities, as the nation prepares to mark the one-year anniversary of the March 11 disaster.
The Japanese government declined to comment on the report.