The incident occurred during one of the festival events at Exhibition Park in Canberra (EPIC) on Saturday.
In one of the videos heavily circulated on social media, two men appear to be arguing with a large group of people wearing hi-vis vests with the words "crowd safety" on the back.
A best mullet competition is among the activities held at the annual Summernats festival. (Dominic Giannini/AAP PHOTOS)
One of the men is punched in the face by a man in a vest, leading to further punches being thrown at members of the public.
In another video, one of the men in hi-vis is physically restrained by others and can be heard saying to someone off-camera "I'll kill you".
Police said they were investigating what occurred and had not made any arrests.
Summernats organisers said they and security contractor Red Dawn were looking into what occurred.
"Summernats and Red Dawn take their responsibilities for the safety and security of everyone at the event very seriously," the festival said in a statement.
"The investigation will be given the highest priority, with outcomes shared and all learnings implemented."
Summernats provides a huge boost to the local economy, drawing most of its crowd from interstate. (Dominic Giannini/AAP PHOTOS)
Two arrests were made at EPIC on Saturday over separate incidents of alleged anti-social behaviour.
Police also responded to a handful of hoon driving incidents after the event concluded.
Numerous defect notices were issued and three vehicles were seized as a result of "hoon driving behaviour", police said in a statement.
"ACT Policing reminds drivers that hoon driving that endangers other road users will continue to be targeted," the statement said.
More than 130,000 people attended the four-day festival, which includes lawn mower racing, a mullet haircut competition, sanctioned burnouts and performances by Daryl Braithwaite and Grinspoon.
While the event brings in tens of millions of dollars for the local economy with 85 per cent of attendees travelling from interstate, some locals complain of burnout smoke and loud revving late at night.
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