An Osaka-based company and its owner have been accused of hiring Vietnamese who overstayed their visas because they were unable to return to their home due to the coronavirus pandemic, investigative sources said Monday.

Police referred those involved to prosecutors without detaining them on suspicion that they helped Vietnamese in Japan work illegally, according to the sources.

The police believe the company used the Vietnamese as a cheap source of labor for its food processing and other businesses. The management has said it did not care about their visa status as long as the company could secure a workforce, the sources said.

"As we hired many people amid a labor shortage, (illegally overstaying foreign nationals) slipped into (our workforce)," the male owner told Kyodo News, adding the company did not check whether the hirees were eligible to work in Japan.

The police have already taken action against four Vietnamese who worked at the company for engaging in activities other than those permitted under their visa.

Among them, a woman in her 20s, who was convicted of the charge, said during her trial at the Osaka District Court that she came to Japan in March last year with a temporary visitor's visa.

Her return flight to Vietnam was canceled due to the virus outbreak and she used up her money while remaining in Japan. The woman engaged in wrapping fruits between June and December in the company's office in Sakai in the western prefecture.