A 23-year-old man had his arm severed and another man suffered shrapnel to the groin in a fireworks mishap during Territory Day celebrations Saturday night, in just one of close to 100 incidents attended to by emergency services on the day.

The man was taken to Royal Darwin Hospital around 8:50pm, along with his amputated arm, where doctors tried to reattach it. It was unclear on Monday if they had been successful.

Another 58-year-old man also went into surgery to have a piece of metal removed from his groin after being struck when a hollow steel pipe that the men were using as a launching pad for fireworks exploded on a Virginia property.

The victims are in serious, but stable conditions, officials said on Monday.

Both men were among six cases that NT paramedics responded to during the day which saw people taken to hospital with burns and other injuries. Close to 100 incidents overall were attended to by emergency services.

A crime scene had been established at the site of the explosion and investigations were continuing, NT Police Northern Watch Commander Sean Patterson said.

Several bushfires were also reported throughout the Darwin CBD and the northern suburbs during Territory Day.

“It was pleasing to see people attend the family-friendly events; however, there were several incidents in the CBD where people were firing firecrackers at crews, off their balconies and even off the roof of unit complexes,” Chief fire officer Mark Spain said.

“Crews attended a structure fire at a unit complex on Smith Street last year and unfortunately attended the same complex again this year to warn residences who were firing crackers off the roof into the busy street.”

Northern Territory Police said merrymakers were generally well-behaved this year.