Black and white voters are increasingly divided about Mayor Bill de Blasio, even though his overall job approval rating is 49 percent and has held steady over recent months, a Quinnipiac University poll showed Tuesday.

The poll found 71 percent of black voters approve of him while only 14 percent disapprove. In contrast, 34 percent of white voters say he's performing well and 50 percent disagree. Among Latino voters, 56 percent approve and 27 percent do not.

"It's a tale of two cities," said Quinnipiac poll assistant director Maurice Carroll. De Blasio's rating is generally "positive and pretty good, but disturbingly ethnically divided," he said.

In Quinnipiac's Aug. 26 poll, de Blasio had an overall approval rating of 50 percent with 65 percent support among black voters and 36 percent among white voters. In a June 11 poll, he had 51 percent approval overall with 66 percent of black voters and 41 percent of white voters in his corner.

The poll surveyed 1,164 voters via landline and mobile phones between Nov. 12 and Monday. It has a margin of error of plus or minus 2.9 percentage points.

Carroll said de Blasio's alliance with the "polarizing" Rev. Al Sharpton may explain the widening race gap.

Police unions have been vocal in their disapproval of de Blasio's friendship and working relationship with Sharpton, a civil rights leader and frequent critic of the NYPD. Former Sharpton aide Rachel Noerdlinger works as the first lady's chief of staff, but announced Monday she was taking an unpaid leave of absence amid her son's arrest, scrutiny over her boyfriend's criminal history and her failure to disclose in a city background check that she lives with him.

In the uproar following the July death of Eric Garner on Staten Island after an apparent chokehold by police, de Blasio convened a meeting at City Hall flanked by Sharpton and NYPD Commissioner William Bratton. Sharpton used the gathering to blast de Blasio and Bratton on police policies.

The poll showed white voters evenly split over whether Sharpton or Bratton had more pull with de Blasio. Black voters by a 3-1 margin regard Bratton as more influential.

By 47 percent to 43 percent, voters overall view Sharpton as a positive force in the city, and among black voters, 79 percent to 14 percent consider him positive. But a majority of white voters -- 64 percent to 28 percent -- deem Sharpton a negative force.

Sharpton said he is "heartened" by the poll. "Despite all the smear attacks, to have over two-thirds of my community ... see our work as positive and important should make people focus on what we do," he said.

A mayoral spokesman said, "Mayor de Blasio will continue to work hard every day doing what New Yorkers elected him to do" on reducing income inequality, improving police-community relations while holding down crime and expanding pre-K education.

The poll also showed 71 percent of voters approve of de Blasio's policy giving police officers the discretion to issue summons in lieu of arrest for people found with up to 25 grams of marijuana.