Japan's so-far sluggish COVID-19 vaccination efforts got a lift Monday as two state-run mass inoculation centers in Tokyo and Osaka got up to full speed one week after their opening.

The two venues, which are run by Self-Defense Forces personnel and due to operate for three months, reached their target of offering a maximum of 10,000 and 5,000 jabs per day respectively as Japan seeks to complete the vaccination of those aged 65 or older, as well those turning 65 this fiscal year, by the end of July.

People head to a newly opened mass coronavirus vaccination center in Tokyo's Otemachi business area on May 24, 2021. (Kyodo) ==Kyodo

The centers were opened to help speed up a vaccination program that is otherwise being run by local governments, with Prime Minister Yoshihide Suga targeting administering up to 1 million doses nationwide per day after mid-June.

Japan can administer around 500,000 doses a day as of Monday, more than double its capacity of 230,000 shots about three weeks ago but still far short of its target, according to a government tally.

To speed up the drive, the health ministry plans to add paramedics and clinical laboratory technicians, as well as qualified doctors, nurses and other medical staff, to give shots.

Suga said his government also plans to expand venues for inoculations to include workplaces and universities. Vaccinations at these places could start as early as June 21, government officials said.

If vaccines are administered at a pace of 1 million doses a day as targeted by the government, daily infections in Tokyo are estimated to peak out at 700 new cases around the third week of August, according to a recent study led by Taisuke Nakata, an associate professor at the University of Tokyo.

In contrast, at a pace of 600,000 daily doses, new infections in the capital would peak out at 1,500 around mid-October, the study showed.

Japan has lagged behind other developed countries in its vaccine rollout. Since its launch in February, initially with health care workers and expanded to the elderly in April, only around 6 percent of the country's 126 million people have received at least one dose.

However, even running at full capacity, the two centers, which are staffed by SDF doctors and nurses as well as private nurses, will only be able to vaccinate 900,000 people in Tokyo and 450,000 in Osaka over the three months of their scheduled operation.

Elderly people living in Tokyo and the neighboring prefectures of Saitama, Chiba and Kanagawa, as well as in Osaka and adjoining Kyoto and Hyogo prefectures, are eligible for inoculations at the centers.

In line with the increase in capacity, the Defense Ministry started Monday accepting reservations from Hyogo and Kyoto for slots in the week starting June 7 at the Osaka center on its website and via the Line message app.

The mass vaccination centers are using the two-dose vaccine developed by U.S. biotechnology firm Moderna Inc. while inoculations conducted by local governments are providing the two-dose vaccine developed by U.S. pharmaceutical company Pfizer Inc. and its German partner BioNTech SE.

In Kobe, the capital of Hyogo Prefecture, local authorities began large-scale inoculations for elderly residents at Noevir Stadium Kobe, home to Japan's pro soccer club Vissel Kobe.

Elderly people receive coronavirus vaccine on May 31, 2021, at Noevir Stadium Kobe in western Japan. The football stadium in Kobe in Hyogo Prefecture opened the same day as a COVID-19 mass vaccination site. (Kyodo) ==Kyodo

The government had planned to vaccinate those with underlying conditions next along with those working for nursing homes after finishing vaccinating the elderly.

But health minister Norihisa Tamura said Sunday that the rollout would proceed directly to those under 65, although those with underlying conditions would receive priority.

With the medical system remaining under severe strain amid the fourth wave of infections, the COVID-19 state of emergency in Tokyo, Osaka and seven other prefectures was extended on Friday by three weeks to June 20 -- just over a month before the Olympics begin in the capital.