One person was killed and four others injured in a shooting at Zombicon in Flordia

Police are still hunting a shooter who opened fire at a Florida zombie festival, killing one person and injuring five others.

Thousands of people dressed as zombies fled when shots rang out about 11.45pm (local time), just as the annual Zombicon event was drawing to a close on De Leon Plaza in Fort Myers.

One man died at the scene, and four others were treated at a nearby hospital for what are understood to be non-life threatening injuries.

Another person who was injured refused medical treatment, local news outlet News-Press reported.

Lieutenant Victor Medico of the Fort Myers Police Department appealed for the public's help to find the shooter.

"There were a lot of witnesses down here, there were a lot of people taking pictures, videos with their cellphone," Medico told News-Press.

"Anything that could help with this investigation would be greatly appreciated."

The annual festival had been expected to draw more than 20,000 fans dressed as zombies, the newspaper said. Medico said the scene was described as "shoulder to shoulder."

Cordons remain in place with armed police patrolling the area.

Zombicon organisers released a statement on Facebook, asking attendees to assist police to find the gunman.

"[We] are deeply saddened by the news of what happened within the footprint of our event.

"We take the safety of our patrons very seriously and take precautions in hiring security and police officers for our annual event. Our prayers go out to the family members and individuals involved in the incident."

ZombiCon has been a popular event for nearly a decade, but some local residents and business owners have not welcomed the crowd of costumed revelers in the street dressed as limping, bloated, degrading corpses. Restaurants posted signs on their doors, warning visitors ZombicCon participants were not welcome.

"Quarantined. No Zombies allowed," the signs read.

Several members from a religious group also picketed the event this weekend.

- Stuff and agencies