A high-speed commuter ferry crashed into a pier near Wall Street at the height of the morning rush hour on Wednesday, injuring 57 people, two critically, the New York City authorities said.

Passengers lying on stretchers littered the pier near South Street Seaport, attended to by firefighters and rescue workers who rushed to the scene of the 8:43am hard landing. Mayor Michael Bloomberg rushed to the scene.

"People who were standing up flew because of the impact," said passenger Brett Cebulash, 50, an attorney who is a daily rider on the 141-foot ferry that caters to white-collar executives.

"It was a normal morning, we were rolling into the dock and then they hit something. There was a sudden impact," he said.

The boat's crew immediately responded to the scene of injured and bloodied passengers, he said.

Some of the injured were taken to the hospital, while others were treated at the scene, a spokesperson for the Fire Department of New York said.

Of the 57 people injured, two were in critical condition with head injuries while nine were deemed serious, officials said.

The National Transportation Safety Board tweeted that its investigators were gathering information about the cause of the crash.

About 327 people were aboard the boat on Wednesday, said Tom Wynne, spokesman for Seastreak, which boasts on its website that its "fast passenger catamarans provide the fastest commute to New York City!"

The accident occurred as commuters queued up to quickly disembark the craft and start their workday.

"The ferry came into the dock hard," Wynne said. "When the vessel hit the dock, the passengers obviously fell."

He declined to name the ferry captain but said, "All of our captains have a great deal of experience."