Royal Adelaide Show organisers confirmed the decision was made out of an "abundance of caution", with the event due to be held from September 5 and 13.
Bird flu cases in the state make up more than three quarters of the national total of 155, the South Australian government confirmed on Friday.
There are 119 confirmed cases in the state, up from 58 at the start of the week.
The Royal Adelaide Show decision will impact about 150 exhibitors, volunteers and stewards in the poultry and bird section.
"While we think the risk is very low, we took the decision now out of an abundance of caution to make sure that our volunteers and exhibitors had as much time to prepare as possible," Royal Agricultural and Horticultural Society of SA chief executive Will Rayner told reporters.
Mr Rayner said the birds were a small part of the overall program, adding there were more than 26,000 competitive entries at the show.
"Obviously we felt that anything we could do to make sure we were as low-risk as possible and also to provide an element of leadership for the industry was the way to go," he said.
There has not been any detections in poultry or in the agricultural production system.
The news comes as a worsening bird flu outbreak sparked debate over whether vaccination is the key to protecting Australian wildlife from the deadly strain.
While the Australian government is conducting pilot studies in non-poultry birds, New Zealand has begun vaccinating some of its rarest birds after completing a world-first research trial in 2025.
About 300 breeding birds were targeted from five species: kakapo, takahe, black stilt, orange-fronted parakeet and shore plover.
Questions have been raised over whether a similar approach would be viable with Australian birds and other animals as the deadly strain's national toll soars past 100.
New Zealand used a different vaccine to the one that features in Australian trials.
Safety and efficacy data is still being gathered, and there are concerns about the logistics and practical application of such a program.
Two doses of any vaccine would need to be administered, with a period of time separating them, experts say.
The task of vaccinating wild animals would be especially challenging, University of Adelaide immunologist Mohammed Alsharifi told AAP.
"If we're talking about vaccinating wild birds, I think that's a big task," he said.
Associate Professor Wayne Boardman, also from the University of Adelaide, said all options should remain on the table.
He said smaller colonies of Australian sea lions could be targeted for vaccination using innovative techniques including dart rifles or syringes mounted on long poles.
"Necessity is sometimes the mother of invention," he said.
There are fears for Australia's seals after a pup with bird flu symptoms died in Victoria.
It is potentially the first seal to be infected with the deadly H5 virus on the Australian mainland.
The federal government has released a susceptibility index, which scales the risk of H5 across native birds and mammals.
David Paton, an ecologist and ornithologist, said vaccination was not a practical solution and called for other proactive approaches in an attempt to contain the virus.
He said birds should have been covered and removed as soon as they began appearing dead and sick along Australia's coastline.
"We should have had a much greater response base in terms of trying to minimise these contact points."
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