The computer network has crashed and been offline for more than a week at a Brooklyn hospital group chaired by a billionaire mega donor to Gov. Kathy Hochul — causing chaos for patients and medical workers, sources said Monday.

Patients from Brookdale, Interfaith and Kingsbrook Jewish hospitals — part of the One Brooklyn Health System — have had to seek treatment at other hospitals amid the cybersecurity mess, which has left medical staffers unable to access patient records, sources told The Post.

The IT crash — which was first reported by The City — is also a potential security risk for patients’ private data, said an industry source, who also blasted state officials for failing to immediately step in and organize a plan to fix the issue.

“A major safety-net hospital system in Brooklyn that receives huge subsidies from the State loses its IT systems and is unable to access patient medical records, laboratory results, etc.  And this has been going on for a week,” the source said.

“Absolutely no coordination with other hospitals in Brooklyn to assist with the patients even though One Brooklyn is transferring patients to them without any explanation.”

At the same time, the industry insider said, FDNY’s EMS service kept sending its ambulances to One Brooklyn hospitals because no one told them that One Brooklyn had an IT problem.

“Absolutely no coordination.  Absolutely no communication.  Where is the [governor’s office]?  Where is the State DOH [Department of Health]?,” the source said.

The state Health Department, which regulates hospitals, issued a terse statement that did not shed light on the cause of the IT system crash.

“We are aware of the incident, and we are working with One Brooklyn Hospital Network to ensure patient safety. As this is an ongoing investigation, we cannot comment further,” said DOH spokesman Jeffrey Hammond.

 One Brooklyn chief executive officer LaRay Brown, in a statement to The City, also gave scant details on the cause of the computer systems crash.

“One Brooklyn Health (OBH) recently experienced an incident resulting in a network disruption. Immediately upon discovering the incident, we took certain systems offline to contain the disruption,” the statement said.

“Our IT team is continuing to work diligently with the support of third-party advisors to ensure that our systems are brought back online as quickly and safely as possible, and in a way that prioritizes patient care.”

Hochul attended a secret meeting in September at the Upper East Side townhouse of Alexander Rovt, who is chairman of the board of the One Brooklyn Health System.

State campaign finance records show Rovt and his wife, Olga, donated the maximum $139,400 combined to Hochul’s campaign.

The state budget — approved by Hochul and the legislature in April — pumped $1.7 billion into a network of “financially distressed” hospitals that include Rovt’s One Brooklyn system.

Cyberattacks against hospitals and other medical facilities are a major problem and often leads to increased patient death rates, according to a study published by the Ponemon Institute.

In a ransomware attack, hackers gain access to an organization’s computer networks, lock up records and data and demand payment. 

Hospitals don’t always disclose to the public when they’ve been victims. But cyber attacks have  steadily increased every year with 297 known attacks last year, according to a survey the cybersecurity company Recorded Future, which was provided to NBC News.

Two-thirds of hospital IT professionals in the Ponemon study who were victims of ransomware attacks said they disrupted patient care, and 59% of respondents found they increased the length of patients’ stays. Nearly one-quarter said they led to increased mortality rates at their facilities.

Safety net hospitals operating in the red or a shoestring budget are prime targets of cyber attackers because they may not have the most advanced IT protections to prevent an attack, industry sources said.