Republican mayoral candidate Nicole Malliotakis said Thursday she wants to bring back suspensions for New York City public school students as young as kindergartners — a practice ended by her incumbent opponent, Mayor Bill de Blasio.

Malliotakis would reverse a 2016 order by de Blasio banning suspensions through the second grade.

“This idea, that the teachers have to go through hoops when they are saying that there is someone who is disrupting their classroom, showing disrespect, bullying other children, bringing in weapons or drugs, is wrong,” Malliotakis said.

In July, the administration announced the suspensions would be replaced with “more age-appropriate discipline techniques.”

For students in upper grades, officials “require documentation of positive supports and interventions provided by the school,” and discourage suspensions.

De Blasio spokesman Eric Phillips said, “when it comes to suspending kindergartners, your goal is either to kick 5-year-olds out of school or it’s not. The mayor believes these young kids should be in school so we can address their underlying challenges and they can learn.”

Malliotakis’ call for a new policy on suspensions came a week after a Bronx teen stabbed two students, one fatally, in history class after they allegedly harassed him.

Before the incident, the NYPD had concluded that the school did not need a metal detector.

Asked at a news conference whether each of the approximately 1,800 public schools should have metal detectors, Malliotakis said “it’s something that should be considered” but the focus ought to be on the most troubled ones.

Phillips said, “with school metal detectors, you either trust the NYPD and their decisions or you don’t. The mayor trusts the NYPD.”

Quinnipiac University released a poll on Thursday that found that de Blasio has the support of 61 percent of likely voters, compared with 17 percent for Malliotakis. About 64 percent of respondents reported not knowing enough about Malliotakis to form an opinion -- down from 78 percent in July.

The poll of 731 likely voters was conducted Sept. 27 to Oct. 4. Its margin of error was plus or minus 4.7 percent.