But Costa, speaking Agencia Estado from Geneva, also said that regulators conditioned their approval of the blockbuster deal by adding restrictions that he declined to specify in detail.
Costa's office in Brasilia could not immediately confirm his remarks, but regulators scheduled a press conference in Brazil's capital for late Tuesday afternoon.
Approval by regulators is the last hurdle for the 4.1 billion EUR deal announced in April that would give Telfonica and the investors a 23.6 percent stake in the former Italian monopoly through an investment vehicle called Telco.
Telefonica and Telecom Italia have overlapping cell phone operations in Brazil. Telfonica owns half of leading Brazilian cell phone operator Vivo Participacoes, and Telecom Italia owns Tim Participacoes, the No. 2 mobile operator in Latin America's largest nation.