Chief Executive Officer Tatsufumi Sakai made the comments on Tuesday at a symposium organized by the Nikkei, she said.

Mizuho, Japan's third-largest lender by assets, will give about 45,000 employees the option to work three or four days a week, the spokeswoman said. It aims to make the option available from December after holding talks with its labour union.

It comes as firms in Japan, known for a strong work ethic and long working hours, have sought to give employees more flexibility during the pandemic, according to a Reuters poll in August.

"We are strengthening the system (for flexible working) so that employees will be able to work more autonomously," said the spokeswoman.

Under the new system, employees who work three days would get 60% of their current salary and those who opt for four days would earn 80% of their income, she added. But employees can still opt to stick to five working days.

Mizuho has allowed more employees to work remotely since April, building on last year's push towards more flexible working. Mizuho last October began to allow employees to engage in side businesses and to take leave to study abroad.

In April, the brokerage arm of Sumitomo Mitsui Financial Group Inc introduced a three-day work week.

(Reporting by Takashi Umekawa; Editing by Ana Nicolaci da Costa)