CSN offered 515p a share for the company, compared with Tata’s previous bid of 500p a share.

If the bid is successful, CSN and Corus will become one of the world’s top five steel companies.

The combined group would produce approximately 24m tonnes of steel a year and, by 2010, approximately 50m tonnes of iron ore.

The merger would enable Corus to secure supply of low cost iron ore from CSN.

Benjamin Steinbruch, chairman and chief executive of CSN, said: “The strategic impetus for this combination is growth - growth in Brazil, in Europe and for our combined workforces. Our goal is to unlock the value of our iron ore assets through Corus, transforming them into cost effective, high quality steel products using Corus' advanced engineering capabilities and its excellent European distribution platform. This is a winning combination for all stakeholders.”