Video footage has already emerged online, including one filmed from a passing vehicle and uploaded to TikTok.
It shows a group of people standing outside the Bader Bargain Centre and a child walking by.
A loud bang is then heard and a firearm blast is visible near several men, one wearing a red bandanna, who take evasive action.
The camera then pans right to another man who appears to be clutching a gun.
A woman filming the incident then says "quick go" before the vehicle accelerates away.
A local business owner told the Herald he heard the blast but did not realise it was gunfire at the time.
The incidents was extremely concerning, he said.
"We have our family working in the shop. Sometimes my kids are working there, so it is worrying."
Asked if gangs were a problem in the neighbourhood, he said: "I think it's like any area within New Zealand. It has improved over the years."
Kiwi Fresh grocery store owner Arun Chadha also heard a loud bang as he was serving customers but thought it was a vehicle being hit in the carpark.
"My goodness. It's definitely a scary incident. It's not very good for customers or shop owners."
Police said earlier they were investigating an incident involving two groups of people in which a firearm was allegedly discharged in Hamilton about 5.30pm.
No one was injured.
"Police are investigating the report and will be making inquiries to locate those involved."
Police could not confirm if gang members were involved.
Earlier this year the Herald reported that newly released police figures showed New Zealand was awash with guns, with frontline officers encountering about 10 firearms across the country every day.
A surge in gun violence has been blamed on simmering gang tensions and organised crime.