Later that day, police searched a Western Heights address after receiving information from the public.
A 27-year-old man was arrested and will appear in the Rotorua District Court tomorrow facing firearm and disorder charges.
Detective Senior Sergeant John Wilson of the Bay of Plenty police said police took this type of offending seriously and inquiries into the matter were continuing.
He said there had been a "real and significant risk to innocent members of the public going about their business with their families on a sunny Saturday morning".
"I am aware that there were many people present when this incident occurred who may be able to help this investigation.
"If you witnessed this incident I urge you to come forward and make contact with the Rotorua police. Police are also keen to obtain any mobile phone footage that may have been captured by witnesses.
"It is only through sheer luck that no one was hurt, and police are determined to identify all those involved and hold them to account for their actions," Mr Wilson said.
Rotorua Lakes Council sport and recreation portfolio leader Charles Sturt said he was left almost speechless after he heard the news.
"It's not what we want to see happening in Rotorua.
"Kuirau Park has undergone a major overhaul, with more plans for the Aquatic Centre, so we can create a family-friendly place.
"Let's hope this is a one-off and I congratulate the police on their swift action.
"This could have been a lot worse if a child or any innocent bystander was hurt.
"These gang members are skating on thin ice," he said.
Rotorua North Rotary Club president elect Noel Hill said he did not hear any gunfire and was alerted to the situation by a woman who told him there were gangs in the area and to call the police.
The Rotary club operates the popular Saturday market in the park.
"The next thing we saw was a police car arriving," Mr Hill said.
"It was further away from us down by the amenity block and I don't think anyone near the market would have had any problems.
"But, obviously this is of concern when that sort of thing happens and it's good to see the police acted fairly quickly to get to the scene."
Rotorua MP Todd McClay said the incident was concerning but was not isolated to Rotorua.
"I think it demonstrates the significant harm the gangs do to communities throughout New Zealand.
"This is not systemic to Rotorua, there are gangs in many parts of New Zealand and I think the police did a very good job keeping on top of them but ultimately the gangs are criminal organisations."
Anyone with information is asked to contact the Rotorua Police Station on (07) 348 0099.
Alternatively, information can be provided anonymously via Crimestoppers on (0800) 555 111.
