The government has previously extended the state of emergency in Tokyo, Osaka, Hyogo and Kyoto until the end of May while expanding it in Aichi and Fukuoka prefectures, reports Xinhua news agency.
The emergency state was initially set to be eased on Tuesday.
Meanwhile, the government is expanding a quasi-emergency to Gunma, Ishikawa and Kumamoto prefectures, Suga said.
At a task force meeting, Suga said Hokkaido, Okayama and Hiroshima will go into stricter restrictions, including a ban on restaurants serving alcohol from Sunday to May 31.
The government had initially planned to put Okayama and Hiroshima under a quasi-emergency while maintaining the one in Hokkaido but it changed course at the request of a panel of experts.
Under the extended state of emergency, restaurants and bars continue to be prohibited from serving alcohol or offering karaoke services and must close by 8 p.m..
Non-compliance will be fined for up to 300,000 yen.
Meanwhile, businesses continue to be encouraged to have employees work from home.