The southern Italian city of Naples celebrated wildly overnight after its football team became Serie A champions for the first time in 33 years, with dozens injured in the revelry, local officials said on Friday.

Mass street partying, punctuated by fireworks, flares, horns and firecrackers, began late on Thursday after the Napoli team secured the title with a 1-1 draw away at Udinese in northeast Italy.

Naples health authorities said 203 people accessed emergency services overnight, including 22 with "red-level" critical injuries and 75 with "yellow-level" serious but not life-threatening conditions.

Health service spokesperson Anna Tagliaferri said the figure was not unusually high, with any of Naples' larger hospitals routinely handling as many as 200 emergency room cases on a "normal" day.

Wild partying had been widely expected over the "Scudetto" title win and authorities had taken several steps to try to contain risks to public order.

The city centre was pedestrianised while fireworks and firecrackers were banned, but that did not stop Neapolitans celebrating with such items throughout the night.

In an unrelated incident, one man died from gunshot wounds. Naples Prefect Claudio Palomba told RAI public radio the shooting had "nothing to do with the celebrations".