New York City Mayor Bill de Blasio’s efforts to end a bitter rift with parts of the police force could be complicated by his liberal allies on the City Council, whose proposed legislation to revise certain law-enforcement tactics are vehemently opposed by police unions.
One bill would require police officers to gain consent before conducting a street search without probable cause or a warrant.
A second would require officers to identify themselves—by name, rank and command—to anyone they stop if there is no arrest or summons.
And a third measure, which Mr. de Blasio has vowed to veto if passed, would make the use of chokeholds a misdemeanor crime.
The first two bills, collectively called the Right to Know Act, have the backing of the majority of the council members, with whom Mr. de Blasio has been closely allied.
Also pushing the legislation: the New York Civil Liberties Union and Communities United for Police Reform, a coalition of liberal groups that helped elect Mr. de Blasio and led the charge against the policing tactic known as stop-and-frisk.
Late in the administration of former Mayor Michael Bloomberg , the city dramatically scaled back the use of stop-and-frisk under scrutiny over the policy that Mr. Bloomberg had once championed.
Mr. de Blasio has lowered the number of stops even more and announced a sweeping retraining of the 35,000-member police force after the death of Eric Garner in July during an encounter with officers on Staten Island.
Supporters say the Right to Know Act, in particular, is the logical next step in a series of policing changes needed to introduce greater respect into everyday interactions between beat officers and young black and Latino men across the city.
“They’re stopped, they’re thrown up against a car or a wall. Their neighbors are looking at them. It’s not always the classic ‘Stop, Question and Frisk’ the way the handbooks would suggest,” said Joo-Hyun Kang, director of Communities United for Police Reform.
“Part of what makes it so hard to trust the police is that there are so many daily interactions that are experienced as disrespect and are dehumanizing,” she said. “This doesn’t have to be the way New York is.”
After months of tension over the death of Mr. Garner, the killing of two officers on patrol and massive protests over police tactics, Mr. de Blasio is looking to build trust with the New York Police Department and support for Police Commissioner William Bratton ’s proposed department changes.
Aides say the mayor believes revising policing techniques should be handled within the department.
Asked about the legislation in November, the mayor said he wants to make sure not to “inadvertently undermine the ability of law enforcement to do its job.”
On Thursday, in a speech to the Brooklyn Chamber of Commerce, Mr. Bratton agreed: “We don’t need additional bills at this time. What we do need from [the council] is additional support—not additional activity that just basically, to our officers, indicates a lack of confidence in them.”
The bills could lead Mr. de Blasio to a confrontation with the council and others in his liberal base.
“They’re on a collision course,” said Doug Muzzio, a professor of public affairs at Baruch College.
Mr. Muzzio said the mayor should proceed “on tiptoes,” even though he probably will veto much or all of the legislation if it is passed, in a show of support for Mr. Bratton.
“The mayor needs to signal that he is not a total left-wing, anti-cop mayor, but a responsible chief executive who leads an effective police department. And that he’s in charge,” Mr. Muzzio said.
Police union leaders say all the legislation would make it harder for officers to do a dangerous job.
“It shows a lack of appreciation for the job that police officers do every day,” said Roy Richter, president of the Captains Endowment Association.
Patrolmen’s Benevolent Association President Patrick Lynch called the legislation an example of the council meddling in NYPD affairs, saying it would lead to “policing that will leave cops standing on the corner like potted palms.”
Councilman Ritchie Torres, a Bronx Democrat and a sponsor of the Right to Know Act, said the consent bill has been misunderstood.
Mr. Torres said the measure would require officers to gain consent for a full search only after an officer’s initial frisk for weapons, when it is clear there is no probable cause or warrant, for example.
“I represent some of the most dangerous neighborhoods. I have no interest in undercutting public safety,” Mr. Torres said.
“If we have to accept broken windows as a fact of life, then we want to make sure those encounters happen with respect,” he added, referring to the policing strategy focused on reducing smaller, quality-of-life crimes.
“Policing should be centered on human dignity,” said Eugene O’Donnell, a professor at John Jay School of Criminal Justice and a former police officer.
“Instead of micromanaging and creating more rules, you recruit the people who are there for the right reasons, and you elevate them, you back them up,” said Mr. O’Donnell.
Write to Mara Gay at mara.gay [at] wsj.com ()