A man suspected of drink driving is in custody after a truck crashed into a crowd watching a parade in New Orleans, injuring 28 people.

Police Chief Michael Harrison says police do not suspect terrorism and the suspect is being investigated for driving while intoxicated.

Harrison says that 21 people were hospitalised after the crash with five victims in guarded condition. Seven others declined to be hospitalised.

The crash happened today at about 1:45pm (NZT) during the Krewe of Endymion parade.

New Orleans Police Department spokeswoman Ambria Washington said that "initial reports show so far that about a dozen people are in critical condition".