Rides banned from this year's Royal Adelaide Show because of safety concerns could still be free to operate in other states due to regulatory inconsistencies, South Australian authorities have warned.

Key points: SafeWork SA has stopped four big rides from operating at this year's show

SafeWork SA has stopped four big rides from operating at this year's show The organisation said it wanted to prevent further deaths, after a fatal accident in 2014

The organisation said it wanted to prevent further deaths, after a fatal accident in 2014 It has warned that rides banned in SA could still be free to travel around the country

SafeWork SA inspectors have turned away four rides from this year's show — which starts on Friday — because of concerns their locking devices fall short of key standards, putting users at risk of being fatally flung at high speed.

The organisation said its regulations have become the strictest in Australia since the death of eight-year-old girl Adelene Leong, who was thrown from a ride at the show in 2014.

SafeWork SA Executive Director Martyn Campbell said the rides found not to comply with safety regulations — The Beast, Speed 2, XXXL and Extreme — were four of the biggest from last year.

A makeshift memorial was set up following Ms Leong's death. ( ABC News: Chris McLoughlin )

He said they lacked a key component on their harnesses to add extra protection in the event of a failure, and have been issued with improvement notices.

"The devices that are present in those four rides do actually have a little redundancy which means if the first locking device fails, the second one activates, but the harness seat pulls forward a little bit," he said.

"It's the locking mechanisms that come over your shoulders that pin you into your seats. There should be two locking devices engineered into that seat which means that if the first one fails, the second one activates.

"That overhead, over-the-shoulder restraint shouldn't move. If it does move, we say it's non-compliant.

"If those shoulder harnesses come forward five to 10 centimetres, someone who's slightly built, or a child could be ejected out of the side of that seat and that's what we're trying to prevent."

Ms Leong was on holidays from Malaysia when she was thrown from the Airmaxx 360 in September 2014, and later died in hospital.

Her death followed other serious accidents on Royal Adelaide Show rides including the Spin Dragon, which injured about 40 people in 2000, and the Twin Flip, which injured two teenagers in 2006.

Adelene Leong died on a Royal Adelaide Show ride in September 2014. ( Supplied by SA Police )

Late last year, SafeWork SA was heavily criticised by anti-corruption commissioner Bruce Lander over its failure to prosecute the operators of the Airmaxx 360 ride.

However, Mr Campbell said the organisation had cracked down in the past 12 months, after a concerning number of deaths associated with rides around the world.

"The community who owns these rides travel around Australia so they operate in every jurisdiction and every state and territory," he said.

"In the case of the Airmaxx ride from a few years back, we know that there was a failure and had something like this been in place, and worked as it should have been, maybe that situation wouldn't have occurred."

'Extra steps' for ride safety apply in SA

Mr Campbell said most rides were made in Europe, making it a challenge to ensure they complied with South Australian legislation.

Almost 40 people were injured by the Spin Dragon ride in 2000. ( ABC News )

He said that the death of Adelene Leong has had a "huge impact" on the local inspection regime.

"We've been working closely for the best part of a year to make sure that these rides are safe," Mr Campbell said.

"If show organisers can't demonstrate that their rides are compliant … then they can't operate in South Australia."

Five years ago, SafeWork SA said that an audit of the Airmaxx 360 had shown no obvious compliance breaches.

Since then, additional regulations have been added specifically covering the operation of rides in South Australia which do not apply in other states.

"The legislation in South Australia is quite different to other jurisdictions. It's a lot more complex and there are extra steps that show rides have to go to comply with safety law here," Mr Campbell said.

"There were some codes of practice which were included in the South Australian Work Health and Safety Act that don't appear in other states. That means there are some additional steps."

SafeWork SA has 13 inspectors dedicated to the show, working with ride owners and show organisers on safety issues.

On-the-spot inspections started today, with a particular focus on about 14 of what it called "newer and more thrilling" rides.

SafeWork SA has described the Royal Adelaide Show, in terms of safety issues, as being on par with the Tour Down Under cycling event and the Superloop car race.