The NYPD will be on high alert at next week’s Greenwich Village Halloween Parade — where costumes can provide cover for extremists looking for “targets of opportunity” as the Israel-Hamas war rages, a cop memo says.

The warning notice, obtained by The Post on Friday, notes that there are no specific or credible threats targeting Tuesday’s parade, which runs from 7 to 11 p.m. along Sixth Avenue between Canal and West 15th streets in Manhattan. 

But the gathering – known to draw about 60,000 people decked out in their spookiest and wildest get-ups – could be an easy target for “malicious actors” looking to do harm, the department said. 

“The large numbers of costumed participants and spectators present a unique challenge for law enforcement authorities providing crowd security, as bulky clothing, masks and props could aid in the concealment of weapons and identities,” the memo says.

Criminals may view popular crowded events such as the upcoming parade “as targets of opportunity” – especially given the Mideast conflict, according to the notice. 

Since Hamas’ unprecedented Oct. 7 raid on Israel, extremists have released guidance “encouraging lone actors to perpetrate reactionary assaults,” according to the memo. 

The disturbing propaganda is largely focused on violence against Jewish sites but also encourages followers to target “Western populations and institutions in general” and offers tactical advice, the memo states. 

As an example of violent extremists striking on Halloween, the memo pointed to the Oct. 31, 2017, attack in which ISIS fanatic Sayfullo Saipov allegedly plowed a van over a crowded bike path along the West Side Highway, killing eight people and injuring at least 11 others, including three children. 

He was sentenced earlier this year to more than eight lifetimes in prison.