(This May 16 story has been refiled to amend quotes to clarify that SoftBank was referring to workers and customers in general, not necessarily its own, in paragraphs 3 and 4)

TOKYO (Reuters) - Dealing with irate customers can be extremely stressful for call centre workers but Japan's SoftBank Corp thinks it has a solution: artificial intelligence-enabled software that softens the tone of customers' voices.

The country's third-largest telecoms provider aims to begin testing the technology internally and externally over the next year and commercialise it by the end of March 2026.

"We are working on the development of a solution that can convert the customer's voice into a calm conversational tone and deliver it to workers using AI-enabled emotion recognition and voice processing technology," SoftBank said in a press release on Wednesday.

"With this solution, we aim for good relationships with customers to be maintained through sound communication while ensuring the psychological welfare of workers."

Japan prides itself on its high standard of customer service but the issue of harassment of staff working in the service industry has gained more awareness in recent years. The government is looking at legislation to strengthen protection for workers.

Around half of some 33,000 respondents to a survey this year by UA Zensen, a labour union for workers mainly in the service and retail industry, said they had experienced harassment by customers during the last two years. The incidents included verbal abuse, intimidation and in some cases even demands by customers for workers to kneel and bow in apology.

More than 100 respondents said they had sought psychiatric help as a result of the harassment.

(Reporting by Anton Bridge and Mariko Katsumura; Writing by John Geddie; Editing by Edwina Gibbs)