A shortage of nurses in New York City schools has reached “crisis level” as dozens of buildings each day — some with multiple diabetic students — are forced to go without a full-time nurse to administer meds and treat injuries, nurses say.

Supervisors are left scrambling to fill the gaps with contract nurses who are less reliable than permanent city RNs, or by shuffling nurses around to different schools throughout the day.

“We are putting children’s lives at risk, and it’s unfortunate that the city only reacts to tragedies — is that what we’re waiting for?” seethed a source in the Office of School Health who spoke on the condition of anonymity.

A second source tasked with assigning RNs to schools said “every morning is like a chess game. Having to call schools and let them know their diabetic students or students with asthma will not have a nurse is extremely stressful.”

In the Bronx, where diabetes and asthma rates are among the worst in the country, nurses are in higher demand and vacancies a regular occurrence.

“Just this week, I had a school with a diabetic student, and there was no nurse in the school, and mom is a single parent. Mom had to find somebody to come and pick up the child,” the source said.

In a separate case, a diabetic child in a Catholic school — religious schools are staffed by city Department of Health nurses — “went for the whole month of September without a nurse,” said the source, who left her desk duties on several days to medicate the child.

At a Bronx public school, a principal was forced to break Department of Education protocol last month and administer an 8-year-old student’s attention deficit disorder medication in the absence of a nurse, according to the source.

A third nursing source said preventive medication is often put on the back burner when no nurse shows up.

“There are all of these students who need pre-gym asthmatic medication … nobody would get their medication,” the source said.

DOH Assistant Commissioner Robert Platt called the shortage “the worst … that he has seen in his tenure” when grilled by parents at a Manhattan District 3 meeting last fall.

Citywide, the DOE said about 2% of its 1,300 buildings — approximately 26 — are without a nurse on an average day.

“We are actively hiring nurses and working closely with DOH on long-term solutions, so all schools have a consistent nurse each day,” DOE spokeswoman Miranda Barbot said. “Approximately 100 nurses are completing training next month.”

One nursing official said “that’s a lie,” noting that on one recent day, there were 23 schools in Manhattan alone without a full-time nurse.

Two more nurses said that in each of their districts, about 10 school buildings go without a nurse on an average day. There are 34 school districts in New York City.

Nurses said the staffing shortage is due to an explosion of medical needs among students, and high turnover among DOH nurses.

In addition to nurses working for the DOH, schools are also staffed by privately contracted nurses and nurses working for the Department of Education.

The United Federation of Teachers, which represents DOE nurses, said the school system needs to hire more to fill the gaps.

“We cannot afford to leave these vital positions vacant,” said UFT official Mary Jo Ginese. “The number of medically fragile students has only grown over the years.”