Brazilian steelmaker Companhia Siderurgica Nacional (CSN) will have to pay BRL 4 billion (US$1.78 billion) to the country's revenue service Receita Federal as a result of unpaid taxes.

According to the nation's fiscal council Carf, CSN did not pay taxes over the net profit the company had after selling a 40 percent stake of the mining company Namisa to Chinese and Korean investors in 2008.

Under the original decision, CSN would have to pay BRL 6.3 billion ($2.8 billion), but Carf revised that amount to $1.78 billion.

According to media reports, CSN adopted an illegal tax plan at the time of the deal.