Following the deaths on Sunday of 20 boat passengers on Lake George, a maritime advocacy group said yesterday that the high level of traffic in New York Harbor could cause a similar accident in the city.

Investigators have not yet determined to what extent a boat’s wake contributed to the capsizing of the tour boat on Lake George, but the Metropolitan Waterfront Alliance has argued for the past five years that turbulent water can send a jolt to passengers on large boats and capsize small craft like leisure boats and kayaks. Fast-moving water also erodes fragile coastlines.

“Unless there’s 20 fatalities in the harbor, it seems like no one is going to pay any attention,” the director of the alliance, Carter Craft, said. “Unless some agency is willing to take a more active role in monitoring harbor traffic, the risk still exists for a tragic incident.”

There are no speed or wake limits in New York Harbor, except under special circumstances such as when docks are being repaired.

The Coast Guard licenses passenger boats and their crews and uses harbor cameras and radar to monitor water traffic from a base on Staten Island, but individual ship captains are responsible for the speed of their vessels.

Ferries, most of which have deep hulls that displace water and create turbulent wakes, comprise the majority of the traffic on New York Harbor.

“By reducing turbulence, it’s got to be safer,” the director of continuing education at Maritime College at the State University of New York, Anthony Palmiotti, said. “At the same time, if you go too slow, you don’t make schedules.”

An increase in harbor traffic in recent years, particularly among water taxis and recreational jet skis and kayaks, prompted the introduction of a bill in the City Council to reduce wakes in sensitive or dangerous areas. Introduced last November, the bill has yet to be voted on by the council’s Transportation Committee.

Mr. Palmiotti said the increased traffic in narrow straits creates choppy waters and dangerously bumpy rides. Captains, he said, communicate with each other in an effort to reduce their wakes, especially as they come around Battery Park in Lower Manhattan, where visibility and reaction time is limited.

Ferry service, he said, is “safer than taking the bus.”

Mr. Craft said he wants the city to create a “waterfront task force” composed of several city agencies to enforce the size of wakes and to educate boaters.