The government padded expenses and had "plants," some of them paid, offer comments and opinions in the state's favor at so-called town meetings over the past five years, an investigating committee said in a final report released Wednesday.

At some meetings, the government tried to manipulate public opinion on controversial policies such as education reforms by recruiting participants to ask prearranged questions favorable to the government position, the report says.

To take blame for the scandal, Prime Minister Shinzo Abe said he will give his salary back to the government for three months. He voluntarily cut his prime minister's salary by 30 percent when he launched his Cabinet in September, as part of ongoing administrative reforms.