Japan's Nuclear Regulation Authority on Friday publicly upbraided the head of operator TEPCO for "rudimentary mistakes" and "inappropriate management of contaminated water" at the devastated Fukushima nuclear power plant.

"I can't help but say that standards of on-site management are extremely low at Fukushima Daiichi," NRA Secretary-General Katsuhiko Ikeda told the head of Tokyo Electric Power Co., Naomi Hirose.

TEPCO needs to increase the size of the staff at Fukushima, if necessary by bringing in workers from other plants, Ikeda said.

The Fukushima plant was devastated in March 2011 by a massive earthquake and subsequent tsunami that disabled cooling systems and led to several meltdowns.

Recent months have seen a succession of stories about leaks of highly radioactive water from the crippled installation.

The operator reactivated earlier this week the Advanced Liquid Processing System, or ALPS, designed to decontaminate radioactive water.

But the ALPS had to be shut down again Friday for hours due to what appeared to be human error.

After apologizing to Ikeda, TEPCO's Hirose vowed to use "all the company's resources, including people, equipment and money," to address the ongoing problems at Fukushima.

The plant is spewing around 300 tons of radioactive water into the ocean every day, according to the Japanese government. EFE