More than half of the nurses working at coronavirus hospital wards have thought about quitting their jobs, a recent survey has found, highlighting the growing strain on the country's medical system during the pandemic.

A total of 118 nurses, or 51.3% of the 230 respondents, said they had either "always" or "sometimes" considered leaving, citing high levels of stress and concerns about getting infected, a survey conducted in January and February by the Japan National Hospital Workers' Union showed.

A second state of emergency was declared for Tokyo, Osaka and other prefectures in January, while a third state of emergency is now in place in many of the country's largest cities.