Animal activists and politicians are calling for a complete ban on rodeos in Tasmania after onlookers at the Royal Hobart Show were left in shock when a rodeo bull broke its hind leg and was seen limping in the arena.

Key points: A rodeo steer had to be put down after suffering an injury on Friday

A rodeo steer had to be put down after suffering an injury on Friday A show sponsor says it will launch its own investigation

A show sponsor says it will launch its own investigation The rodeo company owner says it is rare for an animal to be injured at a rodeo

Visitors, who captured the graphic footage at the Friday event, could be heard saying "don't look at it" and "no-one is helping it" as the animal desperately dragged its disfigured leg.

WARNING: This story includes distressing images.

MC Rodeo Company owner Mick Wyllie, who organised the event, said the bull had "landed awkwardly after jumping".

He said the rider dismounted a few seconds after the animal had left the chute; it then suffered "a complication in one of its hind legs".

The bull was given pain relief and sedated but then had to be euthanased by the event's resident vet.

Emma Haswell says rodeos should be banned. ( ABC News: Jessica Hayes )

Animal welfare campaigner Emma Haswell said holding rodeos was a "gross cruelty" against vulnerable animals.

"It's just time and time and time again animals breaking legs, breaking backs, being tormented and goaded into a frenzy so that they push their bodies into an extreme," she said.

She said it was "extraordinary" rodeos were still being held in the state and she called to ban the events.

"[We] see animals come out of those chutes in pitch dark with blinding lights, the sound of We Will Rock You blasting through the speakers and they just smash into the steel retaining fences," she said.

"There's only one solution — to ban rodeos. They're an appalling thing."

Independent member for Clark Andrew Wilkie agreed.

"This episode also proves again that animals should not be used for entertainment, that the State Government cannot be trusted to safeguard animal welfare and, as we saw with the slaughter of racehorses last week, self-regulation does not work," Mr Wilkie said.

Tasmanian Greens leader Cassy O'Connor has joined the call for a ban.

"Rodeos are cruel, even if the horses and bulls escape injury free. It is animal mental suffering for the sake of money in the name of entertainment," she said.

"This weekend's death has only reinforced the need to ban rodeos. It's long standing Greens' policy, and it's why it is a key part of the Greens' Animal Welfare Amendment Bill — which we have tabled in Parliament."

But Mr Wyllie has defended the way the incident was handled, and rejected suggestions the animal was not immediately attended to.

"We ran some bulls out onto the area to keep him calm — they are the bulls that he travels with — we then removed him from the arena," he said.

"The best approach is not to run out there and try and rescue it because you may put it in danger, put yourself in danger and the outcomes might not be as good as a clear, thought-out process."

"We have a strict code of conduct that we follow set by the Tasmanian Government and we have code of conduct set by our governing body," Mr Wyllie said.

"Freak injuries in rodeo competitions are very, very rare."

In a statement, the event's sponsor — First National Real Estate — said it did not condone or promote activities that might place animals in danger.

"We are immediately beginning an investigation into how the organisers allowed this to occur. Our investigation will be thorough and intensive. We are horrified that the organisers could let this happen," the statement says.

Mr Wyllie said the organisers would conduct their own review to ensure processes were the best they could be.

"Anyone can come and pick our process apart, anyone can come and see our animals being handled and we welcome anyone to come and look at the facts," he said.

The Royal Agricultural Society of Tasmania said animals attending the show for judging and exhibition were subject to strict protocols covering their health, comfort, catering, and wellbeing.