Japan's nuclear regulator on Wednesday said it was halting the screening needed to restart Chubu Electric Power's 9502.T only nuclear power plant, two days after the company reported inappropriate seismic data handling for the regulatory review.

The watchdog's move stalls Chubu's effort to resume two reactors at its Hamaoka Nuclear Power Station on the Pacific coast that have been idled since the 2011 Fukushima disaster, while nuclear plants restart in other parts of Japan.

"This is fabrication of critical inspection data, which I clearly consider misconduct," Nuclear Regulation Authority Chairman Shinsuke Yamanaka told a regular commissioner meeting.

"There appears no objection to halting the review" for the restart of the Hamaoka plant, he added.

Chubu shares tumbled nearly 10% on Tuesday, the most in more than 13 years, after the company said it had used a different method than explained to regulators to select seismic waves for the review.

-Kantaro Komiya/Reuters