Andrew Ansbro, the president of the Uniformed Firefighters Association, center, speaks at a news conference in New York City on Wednesday.
CNN  — 

With New York City’s vaccine mandate for employees set to go into effect this week, officials at the fire and police departments are scrambling to deal with potential staff shortages.

As of Wednesday, about 65% of city firefighters and 75% of police officers had received at least one dose of the Covid-19 vaccine, officials said.

Unions for the two departments have come out against the mandate, which requires city workers to be vaccinated against the novel coronavirus by Friday evening.

City education staff and healthcare workers have been required to be vaccinated for several weeks but other employees had been able to eschew vaccines in favor of frequent coronavirus testing.

As of Wednesday, the Fire Department of New York was preparing for a 20% reduction in service Monday, a source familiar with the ongoing situation told CNN.

Separately, Commissioner Dermot Shea said the New York Police Department is also making plans for shortages.

The mandate will take effect Friday at 5 p.m. ET after a judge on Staten Island on Wednesday denied a request by the city’s largest police union to block the city’s requirements.

Patrick Lynch, head of the New York City Police Benevolent Association and a named party to the suit, said in a statement that the decision was a “violation of police officers’ rights,” and said it would lead to fewer officers on the city’s streets.

“City Hall has given no reason that a vaccine mandate with a weekly testing option is no longer enough to protect police officers and the public,” Lynch said, “especially while the number of Covid-19 cases continues to fall.”

Mayor Bill de Blasio said he wants the employees to get vaccinated by Friday. “If they don’t, they’re going off payroll,” he said.

“Every one of the commissioners has been absolutely confident that they can make the adjustments and every one of the commissioners has adamantly wanted us to move forward with a vaccine mandate. So, I feel ready,” he said.

FDNY may cancel vacations

As many as one-fifth of the city’s fire companies could be closed as a result of unvaccinated staff, the source told CNN, adding that one-fifth of the department’s ambulances may go out of service for the same reason.

The FDNY is planning to cancel vacations and enact mandatory overtime to try to mitigate the expected staffing problems, according to the source, and leadership will be holding virtual meetings with staff throughout the week imploring them to get vaccinated.

The city’s emergency medical services will also seek support by enacting mutual aid with private hospitals and volunteer ambulance services, according to the source.

In a statement shared with CNN, Fire Commissioner Daniel A. Nigro said the department will continue to provide necessary services to the city.

“The Department must manage the unfortunate fact that a portion of our workforce has refused to comply with a vaccine mandate for all city employees,” he said. “We will use all means at our disposal, including mandatory overtime, mutual aid from other EMS providers, and significant changes to the schedules of our members. We will ensure the continuity of operations and safety of all those we have sworn oaths to serve.”

Nigro told reporters Wednesday he believes that FDNY members will get vaccinated.

“We certainly expect pushback. The unions have stated there would be some pushback. I think our members have taken an oath of office to serve the public. They’ve bravely done that for 156 years, they’ve done it through the pandemic, and I think they’ll step up and do it now,” Nigro said.

Two unions that represent firefighters said they will hold a protest Thursday outside Gracie Mansion, the mayor’s home.

Firefighters were told October 20 that they would need to make a decision about the vaccine by this Friday and the unions blasted the city for that timing.

“It’s unconscionable that they’re going to treat these people like that,” Uniformed Fire Officers Association President Jim McCarthy said. “Nine days to make a decision on what’s going to affect the rest of their life with their spouse and their family not being able to weigh in.”

McCarthy also said those who may choose to retire from the department haven’t been given enough time to make that decision.

“That is not enough time to make a retirement decision, if you’re going to retire from this job,” McCarthy said. “We’ve had many of our members that have compensatory time that they’re not going to be able to take off because they have to make a decision. They can’t consult with their spouses, they can’t consult with their families.”

Andrew Ansbro, president of the Uniformed Firefighters Association, said firefighters who don’t get vaccinated will be placed on leave for 30 days but won’t have their medical benefits or union benefits taken away at that time.

He also highlighted again the dedication firefighters have shown during the pandemic.

“For the last 20 months no one can deny that New York City firefighters and New York City first responders and the essential workers have been front and center in this pandemic,” Ansbro said. “Three ways have we’ve been through it and now we’re given a nine day deadline decision on whether or not we’re going to accept the vaccine. We are not anti-vaccine, we are anti-mandate.”

As for the police, Commissioner Shea told New York City TV station WPIX that he planned to tape a final video PSA later on Wednesday encouraging officers to get vaccinated.

The commissioner said that the department was working on contingency plans, which include asking vaccinated NYPD officers to work overtime or double shifts.

There are no plans to bring in additional officers from outside of New York City to deal with potential shortages, he said, adding, “New Yorkers will be safe.”

CNN’s Evan Simko-Bednarski, Lauren del Valle, Taylor Romine, Rob Frehse and Kelly Christ contributed to this report.