The operator of Japan's crippled Fukushima nuclear plant on Thursday was told it could hike household bills by around 8.5 percent, as the president insisted his company was misunderstood by the public.

Tokyo Electric Power (TEPCO) had wanted to ramp up residential customer bills by more than 10 percent to help pay ballooning costs in the aftermath of the disaster, but was told to rein in its rise.

But hours after winning government approval for the huge hike, TEPCO president Naomi Hirose said the reduced rise would cost the company more than $1 billion a year, and said there was a "perception gap" in the way the utility was seen.

Hirose told journalists at the Foreign Correspondents' Club of Japan he would "do his best" to win back public trust in the vast utility.

"I think that someday in the very near future people -- our customers or society -- will be convinced that TEPCO is changing, TEPCO is moving towards (providing) very positive information," he said.

"It is also important that we, Tokyo Electric Power Co, have to be more conscious... of how our customers and society perceive us."

Hirose, who assumed the presidency in June, added: "I am aware there is a huge perception gap. It is important that the company makes efforts to understand what people are thinking of and what people are needing."

But he added the shortfall between the 10.28 percent price rise that TEPCO had wanted and the 8.47 percent they had been granted by the government would result in a serious burden on the firm.

He said revenue is now expected to shrink by some 80 billion yen ($1.02 billion) per year, in addition to a 40 billion yen loss because of the delay in implementing the price rise.

Hirose also fought back over some of the criticism that has been levelled at his company for its handling of the world's worst nuclear crisis since Chernobyl.

In particular, he took aim at a parliamentary report earlier this month that concluded the Fukushima accident was a man-made disaster caused by Japan's culture of "reflexive obedience".

Ingrained collusion between the plant operator, the government and regulators, combined with a lack of any effective oversight, led directly to the worst nuclear accident in a generation, the report said.

"I don't quite understand what facts that finding of collusion is being based on," he said.