The cart was racing in an event quarter-final when it collected the seagull, crashed into a side barrier and collided with its opposition, JB's Pride.

Neither driver was badly hurt but the seagull was injured and later killed.

GALLERY: The day in pictures

MORE: Billycarts add new life to Port Kembla

It was at least the second seagull-related crash of the day and possibly the result of spectators throwing food on to the track to attract birds, according to witnesses.

Think Big won five consecutive championships with Rick Murray at the wheel in the 1970s and 80s, before the event was axed in 1987.

Mr Murray, his father Richard and his son Reece spent countless hours restoring the cart once they learnt the event was being revived.

With Richard now unable to fit inside the cabin, Reece, 20, took over driving and was at the wheel when the accident happened.

"I didn't see the seagull until I got really close," Reece said.

"When I hit it, it felt like a brake had locked on. It buckled the wheel so it wouldn't run straight. I remember looking up the track and seeing [JB's Pride] come at me and clean me up."

He said it was disappointing, especially taking the family history at the event into account.

Both carts were too damaged to finish the race.

Event co-ordinator Val Ochalski, of Red Point Artist's Association, said organisers made an announcement earlier in the day after hearing spectators had thrown food and other debris onto the track.

"I guess you can't keep your eye on everybody.

"If people think it's funny they really need to re-think what funny is."

About 15,000 people attended the event, including large numbers supporting children's soapbox races.

Warrnambool's Alan Treloar, driving Scrounger, won the open division in 25.02 seconds. Fellow Victorian Troy Davey-Milne was second with Sniper while Stephen Thomassini, driving Shaft, was third.