After the bill underwent amendments as it was approved in the lower chamber of congress, the senate ruled that the bill must go through a conciliation process.
GRU Airport's shareholders will inject some US$250mn into the concessionaire.
The debentures will be convertible into shares, although the company did not stipulate the size of the stake to be acquired by the Abu Dhabi fund.
The measure could reduce bureaucracy and speed up work at Brazil's busiest port.
The works on the airport will require an investment of US$86mn and will start in the second half of 2018.
The projects, which requires a total investment of US$158mn, is being backed by the Japan International Cooperation Agency and entails building a 147km export corridor from Paraguay's Argentine border to the Brazilian border.
The measure is part of a new governance policy adopted by the Brazilian company.