Australia's richest woman Gina Rinehart is partnering with Chinese developer Shanghai CRED to bid for S. Kidman & Co, the country's largest private land holding, a source close to the sales process said on Monday.

Rinehart's participation in a bid for the Kidman properties may finally induce Australia's government to approve a sale. The government in April rejected a $A371 million ($279.96 million) bid by a Chinese-led consortium headed by Hunan Dakang Pasture Farming Co Ltd (Dakang) and Shanghai CRED, alongside a minority 20 percent Australian interest, the group's second rejection in six months.

At the time, Australian treasurer Scott Morrison said the sale to the Chinese buyers was not in the national interest and expressed concerns about S. Kidman's vast holdings - about the same size as South Korea - falling into foreign hands.

After the rejection, Shanghai CRED teamed up with Rinehart, with the new alliance expected to launch a rival bid to Dakang, said a source familiar with the sales process and who spoke on condition of anonymity.

Local media reports said Rinehart's group may offer about A$300 million for S. Kidman, a substantial discount to the earlier consortium's rejected bid.

At the same time, the Dakang-led group is determined to launch a fresh bid for Australia's largest cattle business with potential domestic investors to replace Shanghai CRED, a source familiar with the Dakang bid told Reuters.

"The message from Australia's Treasurer is pretty clear in that the deal needs more local participation," said the source. "To have one less Chinese partner means there is more to play with. We are now talking to a number of investors to join the consortium."

Still, Rinehart's close political ties and her nationality may carry more weight in securing government approval.

She is Australia's richest woman with assets worth $11.1 billion, according to Forbes, largely tied to iron ore assets. In August, she named Sophia Mirabella, a former Member of Parliament, as head of government relations for her Hancock Prospecting mining company.

Rinehart is also close to National Party leader and Deputy Prime Minister Barnaby Joyce who opposes additional foreign investment in agricultural assets.

"If Rinehart was offering the same money, we would be very worried," said the source close to the Dakang-led bid.

"There is a disparity in value, which I'm sure reflects certainty. If you have close political links with the leader of the National Party and you have Sophie Mirabella – who is connected to the Liberal Party – you stand a good chance of getting the deal approved."

Mirabella declined on Monday to comment on the bid or Rinehart's participation in a bid.

Local ownership of agriculture is seen as crucial for Australia to cash in on global food demand and to keep tax revenues onshore.

Kidman's 10 cattle stations cover more than 100,000 sq km (25 million acres) of land spread across Western Australia, the Northern Territory, Queensland and South Australia.

($1 = 1.3111 Australian dollars)