"The National Rifle Association and our New York members are outraged at the draconian gun control bill that was rushed through the process late Monday evening," the NRA, the nation's most powerful gun rights lobby group, said in a statement.
"These gun control schemes have failed in the past and will have no impact on public safety and crime," the NRA said.
Also on Tuesday in Danbury, Connecticut, not far from Newtown, gun control advocates gathered for a rally outside a Walmart store to demand Wal-Mart Stores Inc, the nation's largest gun retailer, stop selling assault weapons.
Among those at the rally were Lori Haas, whose daughter was injured in the 2007 shooting at Virginia Tech, and Pam Simon, who was wounded in the 2011 shooting in Tucson, Arizona, that also critically injured former Congresswoman Gabrielle Giffords.
The killings in Newtown, a rural New England town of 27,000, shocked the country and prompted Obama to form a task force headed by Vice President Joe Biden to find ways to curb gun violence. Obama is scheduled to unveil the recommendations on Wednesday.
Obama has signaled he will ask Congress to ban military-style assault weapons, require stronger background checks for buyers and put tighter controls on high-capacity magazine clips.
Opponents of the New York legislation argued it would not prevent an attack like Newtown from occurring in New York and also would not bring down the state's homicide rate because so few murders are committed with rifles of any kind.
Assemblyman Raymond Walter, a Republican from upstate New York, said New York's violent crime statistics show the state has a murder rate of just four people per 100,000, but "rifles account for .03 of that."
Were comparable legislation in place in Connecticut, "it would not have stopped that horrible and tragic crime," said Assemblyman Joseph Saladino, a Republican from Long Island.
The new legislation would also increase monitoring of high-volume ammunition purchases, in-person or over the Internet, and current owners of assault weapons would be required to register them, as is required with handguns.
This week, officials in Maryland and Delaware also vowed to press for their own state legislation to tighten bans on assault weapons and high-capacity magazines.
Included in the New York law is an exemption allowing gun permit holders to opt to have their identities kept private, a measure that comes after the White Plains, New York-based Journal News published the names of thousands of local license-holders.