Guido Mantega said Brazil would not allow its real currency to appreciate excessively and was prepared to take all steps "such as those we adopted in the past".

"If necessary, if the inflows are even stronger, we have (the option) of short-term capital taxes that could (be introduced)," Mantega told reporters on the sidelines of an Economist conference in London.

"We will adopt new measures in terms of taxing of financial operations."

Brazil shocked investors in October 2009 by imposing taxes on some categories of foreign investment flows to local stocks and fixed-income securities. Back then, it said some of the flows constituted hot money and were harming the economy.

Mantega has been one of the foremost critics of the asset buying programmes of 'quantitative easing' that Western central banks have been using to shore up their economies, accusing them of in effect devaluing their currencies to boost competitiveness.