QUEENS, N.Y. - Mayor Bill de Blasio on Wednesday again called on the state and federal government to up the vaccine supply as Citi Field opened to become the city's latest mass vaccination site.

The site will operate 24 hours a day on Wednesdays through Sundays.

However, a lack of vaccine supply means only a total of 800 doses - about 200 a day - will be administered at the new site in its first week.

Half the appointments are being set aside for Queens residents. The other half will be reserved for citywide food service workers and licensed taxi drivers.

Mayor de Blasio reiterated that no walk-ups will be accepted and that anyone looking for a slot must sign up online by going to nyc.gov/vaccinefinder or calling 877-VAX-4-NYC.

"We've gotta get more supply from the federal government and the state government," de Blasio said. "This is the key point. New York City deserves more supply; we could be doing half a million people a week if we had the supply."

One person who spoke with NY1 Wednesday morning said he couldn’t get the vaccine because he showed up with no confirmed appointment.

"It is very frustrating because we tried online," said Dapot Sitorus, a vaccine seeker. "I asked someone to help us online and nothing available. We call, we left a phone number and they never returned our phone call."

"And then at one point I talked to one lady," Sitorus added. "And the lady says, 'sorry we are fully booked.'" 

The Long Island Railroad is opening the Mets-Willets Point stop to accommodate those getting vaccinated.

Trains typically only stop there when there is a Mets game or during the U.S. Open.

Direct service to the site will be available from all stations on the Port Washington Branch.

The MTA says the stop will be made around-the-clock for as long as the site remains open.

Citi Field is also served directly by the "7" subway line and the Q48 bus.