The state's store cattle sales have been red-hot in the past fortnight with plenty of cattle making $4 a kilogram or more.
But some agents believe the market may be close to its peak.
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Thomas DeGaris & Clarkson director Darren Maney said for the good of the cattle industry, he did not want to see prices go "one cent a kilogram higher".
He said the market was heading to "dangerous territory" with those buying light calves for $1300 needing to put a lot of weight on them to reach $2000, at a time when world beef prices were continuing to drop.
We need coronavirus to be over and done with before the major selling season in spring, we can handle any disruption when supply is tight but if the effects hang around the market will be done for.
"Most people buying a 350kg to 400kg steer are starting to have reservations at $1500 to $1600 and look instead at doing a bit of pasture renovation," he said.
While northern restockers were in the market, Mr Maney said prices were really being driven by the southern feedlots looking to secure supply ahead of winter when they know they will be in short supply.
He said it was a big unknown where prices could fall away to in spring.
"We need coronavirus to be over and done with before the major selling season in spring, we can handle any disruption when supply is tight but if the effects hang around the market will be done for," he said.
Elders southern livestock manager Laryn Gogel said eastern states processors had managed to pull the market for finished cattle back a few cents/kg, and expected SA could also follow this trend.
"I tend to think we are at the point where it is probably enough money but I'm not being driven by grass in paddocks, some areas in NSW and Qld have a window of opportunity before it gets cold and they step out of the market," he said. "They are very bullish to get the numbers and get them acclimatised before going through the winter months."
He said there was strong enquiry from the eastern states for trading cattle, which buyers could make a dollar from rather than "pretty" breeding cattle.
"We have a perfect storm of low supply and everyone looking to buy trading cattle which then pushes up the price for feeders," he said.
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