Tens of thousands of New Yorkers had their coronavirus vaccine appointments rescheduled this week due to a lack of supply, Mayor Bill de Blasio (D) said Wednesday.

According to the mayor, a delay in the delivery of Moderna's vaccine contributed to the supply issues, which puts the city's goal of 1 million vaccinations by the end of the month in jeopardy.

"We've had to tell 23,000 New Yorkers who had an appointment this week that they will not be able to get that appointment for lack of supply," de Blasio said during a news conference.

The mayor had said Tuesday that the city needed the federal government to step in to boost their supply, otherwise they would run out of doses and have to cancel appointments.

City Councilmember Mark Levine tweeted Wednesday that 15 vaccination hubs would close Thursday and Friday because of the shortage.

De Blasio and city health commissioner Dave Chokshi said the delayed appointments were for people scheduled to receive their first dose Thursday and Friday, but they were rescheduled for next week.

Chokshi said there was a problem with McKesson, the company the federal government contracted with for vaccine distribution, but he did not have much more information. 

"We expect those vaccines are intact, they will be safe and effective, and we will get them for New York City over the course of today and tomorrow," Chokshi said. 

The delay has impacted 103,400 shots; 54,200 first doses and 49,200 second doses. Instead of getting doses delivered on Tuesday, they were instead being delivered Wednesday and Thursday.

De Blasio said the federal government needs to give cities and states more information about the supply of vaccines, but said he has confidence it will be better under the new Biden administration.

The mayor said he thinks Biden will use the Defense Production Act to break through supply bottlenecks.

"Right now the best solution is what the Biden admin is committed to, expanding supply using the Defense Production Act. We need the supply expanded in a huge way and I truly believe that is what the Biden administration will do," de Blasio said.

He also called on Gov. Andrew Cuomo (D) to release an extra 65,000 doses left over from staff and residents of long-term care facilities who declined to be vaccinated.

"The freedom to vaccinate now involves the freedom to vaccinate the second doses that are being held in reserve," de Blasio said, adding that he is "very hopeful additional vaccines are gonna come into play soon. But we've folks right now who need help, who need to be protected. We need to save lives now."

According to the city's reporting, more than 494,000 doses have been administered, with 434,138 taking a first dose and another 60,458 people receiving the second.