The march near Wall Street Saturday involved hundreds of marchers chanting "shame, shame" protesting alleged income disparity between the wealthy and the rest of the population, the New York Daily News reported.
City officials said the protesters didn't have a public event permit and police moved in on the marchers near sundown, the report said.
Numerous videos and photos were posted online of officers using pepper spray and orange netting on protesters.
New York Police Dept. spokesman Paul Browne issued a statement defending the police actions, The New York Times said.
"There were approximately 80 arrests, mainly for disorderly conduct by individuals who blocked vehicular and pedestrian traffic, but also for resisting arrest, obstructing governmental administration and, in one instance, for assault on a police officer," the statement said.
The demonstration came eight days after Mayor Michael Bloomberg made an uncharacteristic warning on WOR radio that U.S. economic conditions could lead to riots.
"The public is not happy," Bloomberg said. "The public knows there is something wrong in this country, and there is. The bottom line is that they're upset."