Workers at the crippled Fukushima nuclear plant have told the ABC that contaminated water has most likely been seeping into the sea since the disaster two-and-a-half years ago.

Japan's nuclear watchdog has described the leaks as a "state of emergency".

Workers have told ABC's AM program that they do not have much faith in Tokyo Electric Power Company's (TEPCO) ability to handle the situation and they claim another accident is inevitable.

Fujimoto-san, a 56-year-old decontamination worker at the Fukushima nuclear plant, says he has to hide his real job from his two young grandsons for fears they would shun him if they knew.

Key points Workers at the Fukushima plant say contaminated water has most likely been seeping into the Pacific Ocean since the disaster two-and-a-half years ago.

Workers at the Fukushima plant say contaminated water has most likely been seeping into the Pacific Ocean since the disaster two-and-a-half years ago. They say operator the Tokyo Electric Power Company (TEPCO) knew all along but did nothing.

They say operator the Tokyo Electric Power Company (TEPCO) knew all along but did nothing. The workers accuse the company of underpaying them and say another accident at the plant is inevitable.

The workers accuse the company of underpaying them and say another accident at the plant is inevitable. Japan's nuclear watchdog has described the leaks as a "state of emergency".

"We work at the most dangerous place in Japan," Fujimoto-san said.

"Not only that, I work 12-hour shifts and only get paid 11,000 yen."

The wage equates to $125 per shift, or $10 an hour.

Fujimoto-san says if TEPCO caught him speaking to journalists, there would be serious consequences.

"I'd be fired for sure. Speaking out is an act of suicide," he said.

TEPCO has been trying to stop the leak of 300 tonnes of radioactive groundwater every day.

"Steam came out of the Reactor 3 building the other day," Fujimoto-san said.

"When it came out, TEPCO didn't even tell us.

"I found out about it on the TV news after I got home from work."

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He is not the only nuclear worker who believes TEPCO is struggling to cope with the crisis at the Fukushima plant.

Suzuki-san is a 12-year TEPCO veteran and a former Fukushima site foreman.

He says the leaks of contaminated water into the Pacific began in 2011.

"I believe it's been leaking into the ocean from the start of the crisis two-and-a-half years ago," Suzuki-san said.

"TEPCO probably knew this but did nothing because they didn't want to cause an outcry," he said.

While many in Japan worry about another disaster at the Fukushima plant, the welfare of workers there is not often raised.

"There are still reactor buildings we haven't gotten into yet," Fujimoto-san said.

"So there's always the possibility of another explosion, and if that were to happen, we - the workers - would be the first victims.

"I fear that a lot."