China's food giant COFCO is in advanced talks to take full ownership of Noble Group's agribusiness, three sources said, a move which would cement its newfound strength in global agriculture markets and help bolster Noble's balance sheet.

The sources said COFCO was in talks to buy the remaining 49% of Singapore-listed Noble's agribusiness for around $700-$750 million, having already acquired a 51% stake in April 2014 for $1.5 billion.

Noble confirmed in a Singapore Exchange (SGX) announcement that it was in advanced discussions with potential buyers on the sale of its 49% agribusiness stake and other strategic transactions. "No definitive or legally binding documents have yet been signed," it added.

Earlier on Tuesday, Noble declined to comment on the potential COFCO deal.

State-run COFCO was not available for immediate comment.

For COFCO, a deal would reinforce its position among the world's top global agricultural traders, rivaling the "ABCD" quartet of companies -- Archer Daniels Midland, Bunge, Cargill and Louis Dreyfus.

One source said that the big difference in the values between the first deal and a potential second deal showed COFCO had overpaid for the initial 51% stake, but could now mitigate that by paying a lower price for the remainder.

The expected deal would enable Noble's chief executive Yusuf Alireza to follow through on his November commitment to raise $500 million, seeking to retain the company's investment grade credit rating and repair investor confidence after a bruising accounting dispute.

Shares in Asia's biggest commodity trader have shed around two-thirds of their value since mid-February when blogger Iceberg Research alleged the company was inflating its assets by billions of dollars by not fairly representing the value of its commodity contracts.

Noble rejected the claims and board-appointed consultant PricewaterhouseCoopers found no wrongdoing in a report published in August.

The talks with COFCO may or may not result in a deal, however, two sources said they expected a deal to be announced imminently. One said it could be wrapped up by the end of the year and could include an earn out clause based on sugar prices.

The final value of any deal is also subject to change.

The deal would take COFCO's investments in international grain trading in the past two years to around $3.5 billion, including its 51% stake in Dutch grain trader Nidera.

COFCO is expected to raise its stake in Nidera by a further 15% in 2016 as part of an earn out clause after Nidera missed targets in its results following the deal.

The investments give COFCO assets in some of the world's top grain and vegetable oil producing regions, including Brazil, Argentina, Indonesia and the Black Sea area, whilst enabling it to bring food supply to China independently of the dominant ABCD operators.