FILE PHOTO: Shoppers look at Toshiba Corp's Regza television at an electronics store in Yokohama, south of Tokyo, June 25, 2013. REUTERS/Toru Hanai/File Photo

TOKYO (Reuters) - Japan's securities watchdog is investigating Toshiba Corp's 6502.T accounting practices for the last business year to see if it properly handled the losses incurred by its U.S. nuclear unit Westinghouse, a source familiar with the matter told Reuters.

The Securities and Exchange Surveillance Commission is examining the process involved in creating the financial report for the 2016/17 business year, said the source, who was not authorized to speak to the media and declined to be identified.

A Toshiba spokesman declined to comment.