The 29-year-old driver was shot in the abdomen by police and taken into custody after jumping out of the truck with what turned out to be a paintball gun and a pellet gun and shouting "Allahu Akbar!" officials said.
The suspect, who has been identified in US media reports as Sayfullo Saipov, an immigrant from Uzbekistan, was taken to a local hospital but his condition was not immediately released.
Witnesses described a scene of panic and blood, with people screaming in fear and the path strewn with mangled bicycles and bodies that were soon covered over with tarps.
United States President Donald Trump tweeted: "In NYC, looks like another attack by a very sick and deranged person. Law enforcement is following this closely. NOT IN THE U.S.A.!"
Acting Prime Minister Julie Bishop said Australia's Consul-General in New York, Alastair Walton, was in the vicinity of the attack and all embassy and consulate staff have been accounted for.
