Families letting off fireworks at the top of Hawke's Bay's Te Mata Peak on Saturday night ditched the scene once they were confronted about a fire they may have caused, a witness says.
Police are investigating the scrub fire, which left charring on the peak.
Fire communication shift manager David Meikle said they were called to the scene at 9.26pm.
One fire engine was sent from Havelock North and two from Hastings.
It took crews about two hours to extinguish the blaze, he said.
Hastings resident Daniel, who did not want to give his surname, lives within sight of the peak and said he and his partner went up to watch the fireworks.
"We could hear people letting them off up the top so we thought, while we're awake ... we'll go up the top and have a look," he said.
"As we were driving up to the top where the road becomes one lane, we could see the fire on the side of the hill.
"We carried on up and drove right up to the very top carpark, turned around, stopped and parked. I thought, surely they know that fire is there.
"I hopped out of my car, walked over to the side and looked, and as I was doing it, one of the people that was there walked out to the middle of the carpark and puts down a firework and starts letting it off.
"I thought, you've got to be kidding me ... I turned around and go, 'Excuse me, do you realise the hill's on fire?' And they looked at me with a dumb face going, 'What fire? No it's not'."
The groups came over and had a look, then panicked, he said. Someone phoned emergency services, and the people who were letting the fireworks off "jumped in their vehicles and left".
The people setting off the fireworks were a couple of families with children, he said.
Te Mata Peak and its surrounding park are home to native vegetation and wildlife.
The Green Party announced on Wednesday it had written to the environment select committee, asking for public consultation on prohibiting the private use and sale of fireworks.
The party's animal welfare spokesperson, Gareth Hughes, said fireworks started fires, caused accidents, and distressed and sometimes injured animals.
It was time for private sales to end and be replaced by safer public displays, he said.
Source: New Zealand Now