The New York Police Department will reassign plainclothes officers who are part of the city's anti-crime units, NYPD Commissioner Dermot Shea said on Monday.
About 600 plainclothes officers will be immediately moved into detective work, neighbourhood policing and other roles.
"This is a seismic shift in the culture of how the NYPD polices," Mr Shea said.
“It will be felt immediately throughout the five district attorneys' offices. It will be felt immediately in the communities that we protect.”
The plainclothes anti-crime units carry out proactive and preventive policing and do not respond to radio calls.
The NYPD will still have plainclothes officers among the ranks, Mr Shea said.
The move is designed to modernise the country’s largest police force and build trust with communities amid heightened racial tension, he said.
"We welcome reform," Mr Shea said. "Thankfully, here in New York City, angry demonstrations have turned peaceful. Thoughtful discussions about reform have emerged."
New York Governor Andrew Cuomo on Friday signed into law a sweeping package of police accountability measures that received backing after protests over the killing of unarmed African-American man George Floyd in Minneapolis.
The measures include a ban on choke holds and a bill allowing the release of officers’ disciplinary records.
Governor Cuomo said he will sign additional police-based bills into law on Monday.
The new bills will require officers to report firing a weapon within six hours and to provide for the medical and mental health needs of any person under arrest or in their custody.
Police departments and courts must track arrest data, including on race and ethnicity.
Some of the bills had been proposed in past years and failed to win approval, but politicians moved with new urgency after huge, nationwide demonstrations over Floyd’s death at the hands of police.
Members of the New York City Council said they would work to cut $1 billion (Dh3.6bn) in police department spending for the next fiscal year.
The cuts would include overtime, staff numbers through attrition and shifting the department’s responsibilities, the council said.
The proposed cut to the NYPD is about 15 per cent of the $6bn annual budget for department.
Meanwhile, another New York City police officer has been disciplined for action against demonstrators during protests over the death of Floyd.
Mr Shea said the officer was suspended without pay for discharging mace at a group of bystanders during the protests and unrest of June 1.
"Trust is critical to effective policing," he said. "Trust takes a long time to earn and it is very easy to lose.
"We will continue to work relentlessly to earn and keep that trust, because without community partnership we cannot effectively do our jobs."
