The Japanese government is now aiming to give coronavirus vaccines to anyone who wants them by October or November.
Prime Minister Suga Yoshihide made the remark in the Diet on Wednesday.
He said, "In October or November, we want to finish vaccinating all the people who need or want to be vaccinated. I myself will lead all-out efforts to roll out vaccinations and contain the spread of infection."
Japan started inoculations for healthcare workers in February, before expanding them to the elderly.
Companies and universities are set to lend a hand as vaccinations speed up. They will be allowed to give jabs to their employees and students from June 21.
So far, about 10 percent of the population have received at least one dose.
The prime minister and opposition party leaders also discussed the upcoming Tokyo Olympics and Paralympics. Suga was questioned about whether the games can be held safely.
Constitutional Democratic Party leader Edano Yukio said, "You say you will protect the lives and health of the people, while hosting the Olympics," and asked, "Do you mean holding the games will never trigger a spread of infection in the country that would threaten the lives and health of the public?"
Suga said, "We need to take thorough antivirus and strict border control measures to ensure safety and security. By holding the games, we want to demonstrate that the world can be united in the fight against the coronavirus, and overcome this grave challenge."
Democratic Party for the People President Tamaki Yuichiro asked, "How about using the opportunity to introduce a vaccine passport, or a digital certificate that includes negative tests?"
Suga said, "We are considering that matter."
The Olympics will start on July 23 and the Paralympics will get underway from August 24.