BEIJING, July 23 (Reuters) - China on Friday launched an anti-dumping investigation into grain oriented flat-rolled electrical steel imported from Japan, South Korea and the European Union following the expiry of tariffs in place for the last five years.

Those tariffs will, however, be reinstated during the investigation which is due to be completed within a year, China's Ministry of Commerce said.

The probe comes after China Baoshan Iron and Steel and unit of Beijing Shougang petitioned the ministry in May, arguing that an end to the tariffs could lead to further dumping and hurt the domestic steel sector.

Japanese steelmakers including JFE Steel Corp, Nippon Steel & Sumitomo Metal will pay anti-dumping duty rates ranging from 39% to 45.7%. EU tariffs are 46.3% while for those for Korean companies are 37.3%.

The ministry said China would also extend POSCO's price undertaking agreement.

Anti-dumping measures against electrical steel from the United Kingdom have been dropped completely.

Oriented electrical steel or oriented silicon steel is used in transformers and is more expensive than carbon steel.

China is the world's top steel producer. Its oriented electrical steel output stood at around 1.6 million tonnes in 2020.

(Reporting by Min Zhang, Stella Qiu and Dominique Patton; Editing by Edwina Gibbs)