The bidding war for the Corus Group has taken a new turn with Brazil's Companhia Siderurgica Nacional facing a dispute with another Brazilian miner on its capacity to supply iron ore to the Anglo-Dutch steel company.

Sources close to the development said CSN's attempt to take over Corus might be hurt by Brazilian miner Companhia Vale do Rio Doce's plan to challenge CSN's capacity to supply iron ore to Corus.

Sources said CVRD reportedly enjoyed first rights to any extra iron ore from the Casa de Pedra mine under the terms of a contract signed with CSN six years ago. "CVRD will keep a close watch on CSN if it wins the Corus race, on the usage of iron ore from the Casa de Pedra mine," they added.

The dispute over CSN's rights to supply iron-ore to Corus has arisen at a time when rival bidder Tata Steel is believed to be planning to revise its previous offer of 500 pence a share by 7-10 per cent.

Tata Steel and CSN are supposed to finalise their offers for Corus by Tuesday. Otherwise, the UK Takeover Plan will intervene by putting the company under the hammer.

The panel, which has started discussions with three parties -- Corus, CSN and Tata Steel -- may decide on a sealed process where bidders' offers are final or a standard auction is held over a period.

When contacted, a CSN spokesperson said there was no change in the company's position or commitment to acquire Corus. "Should CSN acquire Corus, it will exercise its rights to supply iron ore from its Casa de Pedra mine to all its operations, including those in Europe," he said.

The reported dispute between the two Brazilian companies pushed the closing price of Tata Steel up by 5.77 per cent to Rs 509.25 on the BSE. The Corus stock was hovering at 552.50 pence at the time of going to the press, nearly one per cent over Wednesday's close.