The plan to add a third runway to Changi Airport, announced a year ago to handle a growing number of flights, is proving more challenging than expected.
Engineers have found after extensive tests that the quality of the soil at the site was "very much poorer than expected", Transport Minister Lui Tuck Yew told Parliament on Tuesday.
It will take "a significant amount of time" to prepare the land for the development, he said. But the target is still for Changi to have a three runway system around the early 2020s.
It currently has two, which serve the three terminals there. An existing third runway near Changi Airport is currently used for military flights.
It sits on a piece of reclaimed land which is separated from the existing airport by Changi Coast Road.
To convert it for commercial flights, this third runway will have to be linked to the existing two runways.
There are also plans to build Changi's next mega terminal, T5, next to this third runway. Final plans for the new passenger terminal will be unveiled later this year, Mr Lui said.
When completed in the middle of the next decade, T5 will be able to handle up to 50 million passengers a year, boosting Changi's total capacity to 135 million passengers annually.
While Changi has done well so far, at least two MPs - Mr Cedric Foo (Pioneer) and Mr Charles Chong (Joo Chiat) - expressed concerns that neighbouring airports in Kuala Lumpur, Bangkok, Hong Kong and Dubai were growing at a much faster rate.
Changi's emphasis is sustainable and quality growth, Mr Lui said.
"If we grow at 18 per cent each year like Bangkok and Kuala Lumpur, we will need to double our airport capacity every four to five years, and I think that is certainly not sustainable given our land and manpower constraints," he said.
For the rest of the decade, passenger traffic at Changi Airport is expected to grow by about 4 per cent to 6 per cent annually, he said.
To ensure that Changi remains the region's premier air hub, Singapore will continue to pursue a liberal air policy, Mr Lui said.
For example, Singapore and Indonesia agreed to allow more flights between the two countries last year.
This has led to a 40 per cent jump in the number of weekly flights, Mr Lui said.
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