But the emergency declaration, which Suga aides described as the government's "most important message for the population", has failed to achieve the intended result: reducing contacts among people significantly.
Japan's cumulative total of confirmed coronavirus cases topped 300,000 on Wednesday, according to a Kyodo News tally based on official data. He mostly limited his interventions to asking the public to take basic safety measures such as wearing masks, washing hands and avoiding drinking and dining in groups until mid-December, when he finally announced the suspension of a government-subsidized tourism campaign.
A state of emergency was previously declared in Tokyo, Chiba, Saitama, Kanagawa, Osaka, Hyogo and Fukuoka prefectures in early April during Japan's first wave of infections and was expanded nationwide later that month.
Experts have warned that even the state of emergency measures, which are non-binding and largely rely on voluntary cooperation, may be insufficient to significantly slow the infections.
In addition to Tokyo, which confirmed a record 2,447 new infections on January 7, other prefectures that have huge urban populations, including Osaka and Aichi, have similarly been struggling amid a sudden rise in cases since the start of the year.
Restaurants, pubs and cafes which serve alcohol will also close at that time while gyms, department stores and entertainment facilities will be subject to limited hours, but schools will remain open.
The expansion means that from Thursday, 11 of the country's 47 prefectures will be under the state of emergency - accounting for about 60 per cent of its GDP.
A total of 11 of Japan's 47 prefectures are under the state of emergency, which runs until February 7.
International Olympic Committee President Thomas Bach has also insisted Tokyo 2020 will go ahead in the event's rescheduled slot this year.
A host of COVID-19 countermeasures, such as frequent testing and reducing the stay of competitors at the Athletes' Village, will be in place should the Games take place.
The 2020 Olympic Games originally slated for July of a year ago due to the coronavirus pandemic are now on target to begin on July 23rd.