About half of New York City voters disapprove of Mayor Bill de Blasio’s job performance and say he does not deserve re-election next year, according to Quinnipiac Poll results released Monday.

The poll found 51 percent of respondents say the Democrat isn’t doing well as mayor and 50 percent say he shouldn’t win a second term in 2017.

De Blasio’s newest showing is statistically tied with his worst-ever disapproval rating of 52 percent, taken in May.

Quinnipiac Poll assistant director Maurice Carroll called the results “disturbing” for de Blasio as the election year approaches.

Nonetheless, possible challengers fared worse, the poll found.

In a Democratic primary, de Blasio would get 43 percent compared with City Comptroller Scott Stringer, with 16 percent. Former City Council Speaker Christine Quinn polled at 19 percent.

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Stringer and Quinn have not declared their candidacies.

Carroll told reporters at City Hall the poll shows that de Blasio is “in lousy shape, except with black voters.”

While 47 percent of voters overall have a favorable opinion of de Blasio, 75 percent of black voters view him favorably compared with only 27 percent of white voters, the poll found.

De Blasio spokesman Austin Finan didn’t specifically address the survey results but pointed to the mayor’s record of driving down crime, strengthening the economy and advancing affordable housing and universal pre-K.

“Mayor de Blasio has routinely delivered on the goals set by his administration and remains dogged in his pursuit to make this a fairer and more affordable city for every New Yorker,” Finan said, adding that the results ensure de Blasio’s re-election.

Quinnipiac University surveyed 1,310 city voters via landline and cellphone between July 21 and Thursday. The poll has a margin of error of plus or minus 2.7 percentage points.