It followed a donation earlier this week of R$13 million (£4 million) from Eike Batista, Brazil's wealthiest man.   

Carlos Arthur Nuzman, the President of Rio's bid, hailed the importance of the new partnership.

He said: "We are very happy with the support of Bradesco, which shows the confidence that Brazilian entrepreneurs have in the project.

"It encourages for us to work even harder in this final stage of the campaign."

The money will be used to help Rio prepare for the International Olympic Committee (IOC) Session in Copenhagen, where, on October 2, the host city for 2016 will be chosen.

Rio faces opposition from Chicago, Madrid and Tokyo.

Luiz Carlos Trabuco Cappi, the chief executive of Banco Bradesco, said the investment helped demonstrate Brazil's position as one of the world's leading nations.

He said: "We say that Brazil is part of the modern world and Bradesco is part of Brazil.

"Rio 2016 is a representation of Brazil’s realignment into the international community.

"It deserves all our support and our help."

Banco Bradesco, which was founded in 1943, has 20 million clients and posses the largest network of in the country, with presence in 95 per cent of Brazilian cities.