Vendor Kylie Green said children behaving badly while unsupervised has been an ongoing issue at speedways across Tasmania.

She said children were throwing rocks onto the track and damaging property.

Ms Green her van was damaged at Saturday night's race meet after it was hit by a star picket and rocks.

"We did have an incident of it being hit by a star picket and an incident of rocks being thrown at our van numerous times," she said.

"But we've had ice cream, soft drinks and stuff like that thrown at our van from the top of the grandstand on numerous occasions by children."

She said someone could get seriously injured if nothing changes.

"It is only a matter of time, if parents are not supervising their children a child will get hurt or killed. "

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A post on social media blamed lack of parental supervision for the problems.

Ms Green said vendors may decide not to return to the track if the problem persists.

"Obviously people do not want their vehicles or their vans damaged by this kind of behaviour," she said.

"People spend a lot of money on their stuff to bring to events, so we do need to curb it or vendors will just go, 'look our properties been damaged, we won't come back'."

She said the Carrick speedway management had been trying to stop the behaviour.

"Carrick speedway is doing a great job at trying to make parents aware about what is happening."

It is believed announcements were made over the PA system last night to encourage parents to look after their children and inform them about rocks being thrown.

Ms Green said the speedway shouldn't be responsible for looking after people's children.

"The speedway [management] aren't the ones there to supervise people's children, it's us parents that need to curb this behaviour."

Cranes Combined Carrick Speedway declined to comment until after they had held a debrief on Saturday's event.