Founder Bob Ingham is understood to be asking for about A$1.4bn ($1.5bn) for the business, The Wall Street Journal reported on Thursday, citing unnamed sources.
The figure is based on the business fetching seven-times its fiscal 2013 earnings.
Investec is handling the sale process, the report added.
Previous reports confirmed Blackstone was planning to team up with China agricultural business New Hope Group in its bid to buy the company.
The pair were said to have entered a final round of bids, offers for which were due in mid-December.
Affinity Equity Partners is also understood to have expressed interest in buying the company.
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