Shortly after midnight Friday, Senate Majority Leader Dean Skelos said the bill would be voted on later in the day when Republican lawmakers had reviewed the legislation.
Skelos, of Long Island, said he planned to vote for the legislation and believed there were enough votes to pass the bill in the upper chamber.
The so-called Compassionate Care Act would legalize certain forms of marijuana for severely ill patients. The legislation does not allow the drug to be sold in plant form or smoked, but it can be administered through a vaporizer or in an oil base.
Earlier in the negotiations, Gov. Andrew Cuomo sought to ban smoking the drug, saying it was wrong for the state to promote smoking.
"In the end you have to balance the needs of many of the patients and the truth is we're coming to a point where less and less people smoke ... anyway," said bill sponsor Sen. Diane Savino, a Staten Island Democrat, on Thursday.
Marijuana could be prescribed for at least 10 diseases — including epilepsy, AIDS, ALS and neuropathy — under the direction of the state's health department. The health commissioner would be able to add more illnesses.
If approved by the Legislature, the bill would allow the program to start in as soon as 18 months and would allow a governor to terminate it under advice from the health department or law enforcement.
"Medical marijuana has the capacity to do a lot of good for a lot of people who are in pain, who are suffering and are in desperate need of a treatment that can provide relief," Cuomo said during a news conference with lawmakers.
Doctors would have to undergo training to be eligible to prescribe the drug and could face a felony charge punishable by up to four years of prison if they write fraudulent prescriptions.
The bill does not require insurance companies to cover the cost of the drug.
Patients who sell their prescribed marijuana could face a misdemeanour charge. Patients will be required to carry registration cards showing they are authorized to possess the drug and can be prescribed a maximum 30-day supply.
Five registered growing organizations will be allowed up to four dispensaries each throughout the state, with the counties where the marijuana is grown and sold receiving revenue from an excise tax. Under the stipulation, cultivators must grow the drug indoors in a secure facility.
Cuomo was initially opposed to medical marijuana earlier in his term but proposed a pilot program in January to allow up to 20 hospitals statewide to administer the drug.
He initially wanted a five-year sunset period to evaluate the new program, but negotiations extended that to seven
The Democratic-led Assembly is expected to pass the legislation early Friday.