New York’s “red flag” law goes into effect Saturday, making the Empire State the 17th to put the gun-control measure in place.

The regulations prevent people who show signs of being at risk to themselves or others from purchasing or owning a firearm, rifle or shotgun.

“Saturday is a very big day for saving lives in New York,” said bill sponsor state Assemblywoman Jo Anne Simon (D-Brooklyn) Thursday at a Manhattan rally.

National cries to strengthen gun laws resurfaced after the massacres in El Paso, Texas, and Dayton, Ohio, earlier this month.

“It’s no comfort to deal with a case after someone’s been shot,” Manhattan DA Cyrus Vance Jr. said at a press conference with his Bronx counterpart, Darcel Clark.

“As a district attorney, lowering gun violence is really one of my highest priorities. This is going to save lives, and New York is going to lead the way.”

Starting Saturday, relatives, household members, school administrators or a designee, cops and DAs have the right to file a petition with the state Supreme Court reporting individuals.

Petitioners must provide evidence that individuals own, possess or have access to a firearm and pose a threat to themselves or others.

Applications will be heard and a decision to move forward with a hearing will be made on the same day a petition is filed.

If a person is found “likely to engage in conduct that would result in serious harm to himself, herself, or others,” a temporary “extreme-risk protection order” can be immediately issued, effectively blocking the individual from firearm possession or purchase, according to the legislation.

Such an order would allow law enforcement to immediately remove any guns from the person’s home.

A follow-up hearing would be held within three to six days to decide whether to keep the weapons out of the home for up to a year. Such orders can be renewed after that.

“We are pulling together a task force to monitor this process,” said state Senate sponsor Brian Kavanagh (D-Manhattan/Brooklyn), noting cohesion among the Legislature, Gov. Andrew Cuomo’s office, district attorneys’ offices and school superintendents.

“If an order is being granted, from my perspective that’s a good thing,” he added. “We don’t think it’s going to be a very high volume. The Office of Court Administration hasn’t asked us for additional funding.”

Cuomo signed the legislation in February.