Premier Jay Weatherill has again defended his government's decision to sell a prime piece of industrial land without going to public tender.
In December, the government announced it had sold the 400ha site at Gillman, in Adelaide's north, for $100 million.
The exclusive deal gives development consortium, Adelaide Capital Partners, six months to come up with a plan for the site before committing to the purchase.
The Australian and The Advertiser newspapers have reported that two other waste management companies were considering legal action over the sale.
But Mr Weatherill told reporters on Friday he had "not heard such nonsense in my life".
The accepted proposition would deliver a piece of economic infrastructure to SA, where the developer accepted the risk, paid for the land and at the end SA would have thousands of jobs, he said.
Nobody else had offered "anything of the sort", with one proposal being for an eighth of the piece of the land "where we would have paid them money, where we accepted the risk", he said.
"If we had hesitated about this (accepting the deal) and put it out to tender and this proposition disappeared, we would have been justly criticised for not seizing an incredibly important opportunity," he said.
"All we have given them is a period of exclusivity for them to take the next step in what is a massive project."
Opposition treasury spokesman Iain Evans had called on the government to reveal just how many developers expressed interest in Gillman, the nature of the proposals and how they were assessed.
"How do we know taxpayers got the best value for money?"
"A government that has almost $14 billion of debt, a $1 billion deficit and a $1 billion interest bill can't afford to get anything less than full value for the public assets it sells."
Mr Weatherill said the opposition was being hypocritical, given that its leader Steven Marshall met with the proponents in December and said he supported the arrangement.
"So what he then does is disappear into the shadows and allows one of his front benchers to come out and question the deal."
