A 25-year-old man accused of driving a pickup truck into a crowd of spectators at a Mardi Gras parade in New Orleans was arrested and charged with injuring 28 people in a crash that brought chaos to the city's signature celebration, authorities said on Sunday.

New Orleans police booked Neilson Rizzuto after taking him into custody in "a highly intoxicated state" immediately after the accident on Saturday evening, the department said.

Police talk to a man sitting in a car that was struck by a pickup truck that slammed into a crowd and other vehicles, injuring several people, during a Mardi Gras parade in New Orleans. (Gerald Herbert/Associated Press)

Rizzuto was charged with two charges of vehicular negligence injuring in the first degree, hit-and-run driving and the reckless operation of a motor vehicle, according to a statement.

No further information about him was immediately available.

New Orleans police talk to possible witnesses to the crash along the Krewe of Endymion parade route in the Mid-City section of New Orleans. (Chris Granger/NOLA.com The Times-Picayune via AP)

The truck driven by Rizzuto was travelling along the side of the street open to traffic along the parade route in the Mid-City neighbourhood of New Orleans when it struck three vehicles, including a dump truck. It then veered onto the median where a crowd of people stood watching the procession, police said.

Five people were being treated at hospital trauma centres and an investigation is ongoing, police said.

People console each other as they watch New Orleans police work the scene where a vehicle plowed into a crowd, injuring several people. (Chris Granger/NOLA.com The Times-Picayune via AP)

Police immediately apprehended the driver, who according to eyewitnesses interviewed by Fox television appeared disheveled, glassy-eyed and under the influence of drugs or alcohol.

In a statement, Mayor Mitch Landrieu referred to the suspect as a "drunk driver."

People walk away from the scene of Saturday night's crash. (Shannon Stapleton/Reuters )

Video footage from the scene showed pandemonium immediately following the incident, but the Krewe of Endymion parade, the largest and most popular of numerous Mardi Gras season parades in New Orleans, continued with little or no interruption.

Of the 28 people injured, 21 were taken to local hospitals, including one police officer. Seven others who were hurt declined transport, Police Chief Michael Harrison told a news conference.

Authorities on Sunday identified 25-year-old Neilson Rizzuto as the man who allegedly plowed a vehicle into people watching a Mardi Gras parade in New Orleans, injuring 28. (New Orleans Police Department)

Local media reports said 12 people were initially listed as critically injured.

Harrison said police believed the motorist who was arrested was being questioned at the police department's drunken-driving office.

The Federal Bureau of Investigation in New Orleans said its agents were "co-ordinating with our federal, state and local law enforcement partners to determine whether a federal violation has occurred."

The Endymion parade incident was not the only one to mar Mardi Gras festivities in New Orleans on Saturday. Earlier in the day, someone's gun went off accidentally in a portable toilet along the route of another, smaller parade, leaving one person wounded, police said.