Gina Rinehart's rivals for S. Kidman & Co farms

The controversial bidding process run by EY for the S Kidman & Co farms has seen some of Australia's wealthiest graziers denied access to the properties in order to make a bid.

BRW Richlisters Tom and Pat Brinkworth and Sterling Buntine are challenging Gina Rinehart's bid to secure Australia's largest land holder, according to The Australian Financial Review.

The all-Australian syndicate, which also includes the Harris and Oldfield families, has reportedly been denied access to the properties in order to make a bid.

Mrs Rinehart's Hancock Prospecting and Shanghai CRED has an well-advanced bid worth more than $365 million on the table.

The paper reports there is a $3.8 million break fee between S.Kidman & Co and the Hancock joint venture if either decide to walk away.