Although Brazil had slow economic growth and high inflation last year, she is popular, partly because of that stand on corruption.
Mr Key said many New Zealand companies were interested in Brazil and there was a lot of room for expanding current investments.
Fonterra has identified Brazil as the market with most potential for it, just above Mexico. Brazilian mining company Petrobras could also be discussed - Petrobras recently pulled out of its mine exploration permits in New Zealand, which Mr Key said was partly due to domestic issues in Brazil.
"We might find out what is going on but we won't push it too hard."
Wooing Brazil in trade is considered to be harder work than with countries such as Mexico and Chile. It is a major food producer itself and there is a high internal demand, so it does not rely on international trade as much. It also leans to the Atlantic rather than the Pacific in international relations.
Brazil's medium-term attention is increasingly on the major sports events it is due to host - the Fifa World Cup in 2014 and the Olympics in Rio de Janeiro in 2016.
Supporting Brazil's bid to become a permanent member of the Security Council could help New Zealand's case, but Mr Key said New Zealand's position was for an interim measure in which some of the larger countries were given extended terms on the council, until there was reform.
Brazil
*New Zealand's 49th largest trading partner.
*Exports to NZ: $112 million - vegetables, fruit, coffee and tea.
*Imports from NZ: $81.3 million - chemicals, machinery.
*More than 2000 Brazilian students studied in NZ last year.
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