The news follows the announcement that financing deals will be signed by the Kenya Airports Authority by the end of 2012.
Expected to be completed in 2017, the expansion will help the airport handle about 20 million passengers per year.
JKIA expansion project manager Francis Ngigi told Business Daily that a number of financiers had been selected and a decision would be made in November 2012.
"We are in advanced negotiations having identified a number of international lenders based on their loan terms," Ngigi said.
"We will be making the final decision in December."
Financiers include China Development Bank, with the debt set to be paid back through airport tax, which would be doubled from $20 to $40.
Designed to handle 2.5 million passengers per year, the current terminal is handling 6.5 million passengers and the airport is expecting 17.1 million passengers per year by 2020 and 35.3 million after ten years.
Anhui Construction Engineering Group (ACEG) and China National Aero-Technology International Engineering (Catic) will carry out the work in collaboration with Pascall + Watson Architects.
According to JKIA, the delay in project would force KAA to build a temporary terminal to handle the rising passenger traffic.
JKIA is also planning to begin construction of 5,500m-long second runway in June 2013 with an investment of $147.9m (KES 12.8bn).
In addition to the runway project, JKIA has also lined up several modernisation projects including construction of a new unit, Terminal 4, refurbishing the existing Terminals 1, 2 and 3, and construction of remote stands to part aircraft.
Image: Construction of the Greenfields terminal would allow airport to handle 20 million passengers per year.