A hate-spewing homeless man punched an elderly Asian man in the head in Midtown in an unprovoked assault, cops said Friday.

The random attack unfolded just after 10:30 a.m. Thursday as the 81-year-old man was walking near 420 Lexington Ave., according to police.

The 55-year-old alleged attacker, who was identified as Barry Morris, knocked the elderly man to the ground while shouting, “We have to get rid of all the ninjas!,” police said.

The 81-year-old was taken to NYU Medical Center, where he was treated for a fractured hip and bruises on his head, cops said.

Morris was arrested at the scene and charged with assault, cops said.

The NYPD’s Hate Crime Task Force is probing the attack as a possible hate crime, cops said.