A 4-year-old boy was critically injured by a motorcyclist who slammed into him, then sped off in a Queens park on Sunday night, police said.

The child was struck by the male driver who was riding in between cars in the boathouse parking lot at Flushing Meadow Park at about 5:50 p.m., according to police and sources.

The suspect sped away from the scene on his motorcycle after striking the boy, police said. He was being sought Sunday night.

The victim was taken to Cohen Children’s Medical Center in critical condition, police said.