Suga, who was speaking at the opening of a new parliament session, has only been in office since September, but has seen approval ratings nosedive over his government's handling of a third wave of infections.
The governors of Osaka, Kyoto and other hard-hit prefectures asked the government to announce the emergency.
A declaration of a state of emergency is a powerful means, based on the law, for tackling the spread of infections, but it also places big restrictions on people's lives.
Responding to pressure from Tokyo and three neighbouring prefectures in eastern Japan, Suga last week declared a state of emergency for the greater metropolitan area.
According to Japanese Prime Minister Yoshihide Suga, the dekayed Tokyo Olympics would go-ahead as scheduled in July 2021, even as the country grapples with an unexpected surge in coronavirus cases.
The games, now scheduled for July, involves over 11,000 athletes across the globe with a combined budget of $15 billion.
Japan's Prime Minister Yoshihide Suga on Monday abruptly halted the subsidy programme over the year-end after the country saw a resurgence in coronavirus infections.
The Bank of Japan can also promote green finance by setting ESG guidelines for its asset management, which would send a message to private banks that they should do so too, she said.
The country recorded more than 3,000 new infections for the first time in one day on Saturday and Tokyo, Japan's largest city, confirmed 621 new cases.
Prime Minister Yoshihide Suga on Tuesday announced his plan to compile a 73.6 trillion yen stimulus package to speed up the country’s recovery from its deep coronavirus slump.
Hydrogen product maker Iwatani jumped 10.1% after the Nikkei business daily reported that the Japanese government was likely to set a target to expand the use of hydrogen to 10 million tonne by 2030 to meet its emission goal.
Main issues that will be discussed at the panel include how to improve labour mobility and productivity, as well as business restructuring in a post-coronavirus world.