Hundreds gathered outside a Parks Department hearing on the proposal, chanting "artist power" and holding signs that accused the city of harassing artists. Inside, protesters occasionally disrupted the proceedings with the same message.
The Bloomberg administration is proposing new rules that would shrink the vendor population by up to 80 percent in some areas of the city's most famous parks.
The number of art vendors - popular with tourists and part of the cityscape for decades - would be dramatically reduced in Union Square, Battery Park, the High Line Park and parts of Central Park.
The administration says those areas have become too crowded, and even dangerous.
"There are places where there are so many vendors, you can't get down the sidewalk," Bloomberg said Friday on his weekly radio show.
There are typically around 300 art vendors operating among the four parks covered by the proposed rule. The regulation would cut that to a total of 81.
Central Park's restricted areas would be allowed a total of 49 vendors - nearly half of them in front of the Metropolitan Museum of Art, and the others between Columbus Circle and Fifth Avenue.
Union Square would get 18, Battery Park would get nine and the High Line would get five.
Artists say the proposed caps are unconstitutional. A federal appeals court sided with the artists when the previous administration tried to limit street art vendors.
The city said there would be no immediate decision. The purpose of the hearing was to gather comment.