Changi has awarded a second contract, worth $1.11 billion, to develop a three-runway system that will allow the airport to handle more flights as the demand for air travel increases.
The first contract, of an almost similar value, was awarded in October.
Changi currently operates with two runways but will add a third strip as part of the development of Changi East, which includes the massive new Terminal 5.
The third runway will be the one currently used for military flights.
It is separated from the current airport premises by Changi Coast Road which is being diverted to accommodate Changi's expansion plans.
To prepare the runway for commercial flights, it will be lengthened and connected to the two existing runways via a 40km network of taxiways.
In an announcement yesterday, Changi Airport Group (CAG) said the latest tender has been awarded to a joint venture comprising Hock Lian Seng Infrastructure and Sembcorp Design and Construction.
There will be more contracts to come to prepare the third runway for commercial operations, the airport said. The whole project is expected to be completed by the early 2020s.
The scope of the current contract includes pavement and drainage works, mechanical and electrical works, as well as supporting works such as road diversions.
Mr Yam Kum Weng, CAG's executive vice-president, development (Changi East & Terminal 4), said: "The development of a three-runway system is an important part of Changi Airport's expansion plans, which will take the Singapore air hub into its next phase of growth."
He added that the project is "complex and requires meticulous planning and excellent execution".
The development of Changi East and construction of T5 are aimed at solidifying Changi Airport's position as a premier hub for global and regional passengers.
T5, slated to open at the end of the 2020s, is currently planned to handle up to 50 million passengers a year which will boost Changi's total capacity to 135 million a year.
In a recent report - its first detailed analysis on Changi's growth trends - leading industry consultancy OAG said the additional capacity could be fully utilised by 2032 or even earlier.
The forecast is based on past traffic patterns, plans by home carrier Singapore Airlines and developments in the region.