Gov. Andrew Cuomo on Monday ordered the state health department to probe allegations of “horrific” overcrowding and understaffing at Mount Sinai Hospital’s emergency department following a Post exposé.

“The reports of mistreatment of patients is horrific and unacceptable,” said a Cuomo spokeswoman.

“Governor Cuomo has directed the New York State Department of Health to review the complaints made against the hospital in this story and, if warranted perform an investigation into any credible allegations,” the rep added.

Current and former nurses and a doctor from the Upper East Side hospital told The Post that the ED is overwhelmed by staffing shortages.

Insiders said the chaotic scene — likened by one source to a “war zone” — has resulted in patients going into cardiac arrest without anyone noticing, and nurses treating up to 18 patients in a shift.

A 2018 report obtained by The Post showed that three independent medical directors brought in to exam the ED said the conditions were “among the worst we have ever seen.”

Cuomo wasn’t the only pol appalled by what he read.

“It’s sad that Mount Sinai is apparently putting profit before people’s lives,” said City Councilman Robert Holden (D-Queens), a member of the Council’s Committee on Health.

“This is an apparent black eye to a hospital that once had a great reputation because of its patient care,” added Holden. “I’d be interested to hear Mount Sinai’s reasons for this reported deterioration.”

Councilwoman Carlina Rivera (D-Manhattan) also weighed in.

“The serious issues outlined in the report commissioned by Mount Sinai three years ago are very disturbing, and the claims highlighted in this article by multiple nurses show that little has apparently changed at a critical hospital in our city,” said Rivera, the chair of the council’s Committee on Hospitals.

“When nurses are forced to take care of 18 patients at a time — regardless of whether they have been officially assigned to them — in order to make sure patients are receiving life-saving treatment, it just shows why the state Legislature must pass real safe staffing laws in 2020,” she added.

Rivera was referring to a bill sponsored in Albany by Assemblyman Richard Gottfried (D-Manhattan) that would set a limit to the number of patients that nurses in hospitals and nursing homes can care for.

“The conditions described in the story are shocking,” said Gottfried, who chairs the Assembly’s Health Committee. “As advocates and legislators have said for years, we already know that safe staffing ratios are needed to save lives and improve patient outcomes.”

A spokeswoman for Mount Sinai, which has denied the claims of its employees as “simply not true,” declined to comment Monday on the Cuomo-directed state investigation.