ALBANY — Joining a growing group of states that have loosened restrictions on marijuana, Gov. Andrew M. Cuomo of New York plans this week to announce an executive action that would allow limited use of the drug by those with serious illnesses, state officials say.
The shift by Mr. Cuomo, a Democrat who had long resisted legalizing medical marijuana, comes as other states are taking increasingly liberal positions on it — most notably Colorado, where thousands have flocked to buy the drug for recreational use since it became legal on Jan. 1.
Mr. Cuomo’s plan will be far more restrictive than the laws in Colorado or California, where medical marijuana is available to people with conditions as mild as backaches. It will allow just 20 hospitals across the state to prescribe marijuana to patients with cancer, glaucoma or other diseases that meet standards to be set by the New York State Department of Health.
While Mr. Cuomo’s measure falls well short of full legalization, it nonetheless moves New York, long one of the nation’s most punitive states for those caught using or dealing drugs, a significant step closer to policies being embraced by marijuana advocates and lawmakers elsewhere.
New York hopes to have the infrastructure in place this year to begin dispensing medical marijuana, although it is too soon to say when it will actually be available to patients.
Mr. Cuomo’s shift comes at an interesting political juncture. In neighboring New Jersey, led by Gov. Chris Christie, a Republican whose presidential prospects are talked about even more often than Mr. Cuomo’s, medical marijuana was approved by his predecessor, Jon S. Corzine, a Democrat, but was put into effect only after Mr. Christie set rules limiting its strength, banning home delivery, and requiring patients to show they have exhausted conventional treatments. The first of six planned dispensaries has already opened.
Meanwhile, New York City’s new mayor, Bill de Blasio, had quickly seemed to overshadow Mr. Cuomo as the state’s leading progressive politician.
For Mr. Cuomo, who has often found common ground with Republicans on fiscal issues, the sudden shift on marijuana — which he is expected to announce on Wednesday in his annual State of the State address — was the latest of several instances in which he has embarked on a major social policy effort sure to bolster his popularity with a large portion of his political base.
In 2011, he successfully championed the legalization of same-sex marriage in New York. And a year ago, in the aftermath of the mass school shooting in Newtown, Conn., Mr. Cuomo pushed through legislation giving New York some of the nation’s toughest gun-control laws, including a strict ban on assault weapons. He also has pushed, unsuccessfully so far, to strengthen abortion rights in state law.
The governor’s action also comes as advocates for changing drug laws have stepped up criticism of New York City’s stringent enforcement of marijuana laws, which resulted in nearly 450,000 misdemeanor charges from 2002 to 2012, according to the Drug Policy Alliance, which advocates more liberal drug laws.
During that period, medical marijuana became increasingly widespread outside New York, with some 20 states and the District of Columbia now allowing its use.
Mr. Cuomo voiced support for changing drug laws as recently as the 2013 legislative session, when he backed an initiative to decriminalize so-called open view possession of 15 grams or less. And though he said he remained opposed to medical marijuana, he indicated as late as April that he was keeping an open mind.
His shift, according to a person briefed on the governor’s views but not authorized to speak on the record, was rooted in his belief that the program he has drawn up can help those in need, while limiting the potential for abuse. Mr. Cuomo is also up for election this year, and polls have shown overwhelming support for medical marijuana in New York: 82 percent of New York voters approved of the idea in a survey by Siena College last May.
Still, Mr. Cuomo’s plan is sure to turn heads in Albany, the state’s capital. Medical marijuana bills have passed the State Assembly four times — most recently in 2013 — only to stall in the Senate, where a group of breakaway Democrats shares leadership with Republicans, who have traditionally been lukewarm on the issue.
Mr. Cuomo has decided to bypass the Legislature altogether.
In taking the matter into his own hands, the governor is relying on a provision in the public health law known as the Antonio G. Olivieri Controlled Substance Therapeutic Research Program. It allows for the use of controlled substances for “cancer patients, glaucoma patients, and patients afflicted with other diseases as such diseases are approved by the commissioner.
Mr. Olivieri was a New York City councilman and state assemblyman who died in 1980 at age 39. Suffering from a brain tumor, he used marijuana to overcome some of the discomfort of chemotherapy, and until his death lobbied for state legislation to legalize its medical use.
The provision, while unfamiliar to most people, had been hiding in plain sight since 1980.
But with Mr. Cuomo still publicly opposed to medical marijuana, state lawmakers had been pressing ahead with new legislation that would go beyond the Olivieri statute.
Richard N. Gottfried, a Manhattan Democrat who leads the assembly’s health committee, has held two public hearings on medical marijuana in recent weeks, hoping to build support for a bill under which health care professionals licensed to prescribe controlled substances could certify patient need.
Mr. Gottfried said the state’s historical recalcitrance on marijuana was surprising.
“New York is progressive on a great many issues, but not everything,” he said.
Mr. Gottfried said he wanted a tightly regulated and licensed market, with eligible patients limited to those with “severe, life-threatening or debilitating conditions,” not the broader range of ailments — backaches and anxiety, for instance — that pass muster in places like California, which legalized medical marijuana in 1996.
“What we are looking at bears no resemblance to the California system,” Mr. Gottfried said.
While he was aware of the Olivieri statute, he believed it had not been implemented because it would have required “an elaborate administrative approval process,” which he said could be overly burdensome on patients.
Ethan Nadelmann, the executive director of the Drug Policy Alliance, praised Mr. Cuomo’s decision as “a bold and innovative way of breaking the logjam” in Albany, though it may not be the final word on medical marijuana.
Mr. Cuomo “remains committed to developing the best medical marijuana law in the country,” Mr. Nadelmann said. “And that’s going to require legislative action.”
The administration has much work to do before its program is operational: For starters, it must select the participating hospitals, which officials said would be chosen to assure “regional diversity” and according to how extensively they treat patients with or research pertinent illnesses like cancer or glaucoma.
Another hurdle: State and federal laws prohibit growing marijuana, even for medical uses, though the Obama administration has tolerated it. So New York will have to find an alternative supply of cannabis. The likely sources could include the federal government or law enforcement agencies, officials said.