Major works are expected at Terminal 1 in the coming months during the development of Changi Airport's new "Jewel" complex.
The largely retail building, to open in 2018, will be erected on the site of T1's current open-air carpark, though minimal disruption is expected in the meantime.
The airport is considering moving some shops and restaurants out of T1, which will be linked to Jewel, to make more room for passenger processing and boost total handling capacity from 21 million passengers a year now to 24 million.
The T1 planning team is also looking at getting rid of the existing check-in rows and building new ones as it pushes for more self check-in and other facilities.
Changi Airport Group is working with industry consultancy Airbiz Aviation Strategies to study several options. These include having machines that can be used for self-service check-in and bag tagging and, when needed, be converted into manned counters.
Another option is to have fewer check-in rows to make space for a dedicated area for as many as more than 50 self-service machines.
A spokesman for Changi Airport Group told The Straits Times that "to enhance productivity, improve operational efficiency and refine the airport experience for passengers", there are plans to introduce new initiatives for passenger handling and other processes across all terminals.
The details for T1 are still being finalised, he said.
With manpower constraints and increasing costs, ground-handling firms are finding it tough to find and keep staff to handle passenger and baggage processing as well as other ground operations.
Alternatives like self-service check-in systems are commonly used at airports in the United States and Europe but less so in Asia.
The International Air Transport Association is leading the drive to implement such systems globally with its Fast Travel project. Its vision is to have end-to-end self-service processing which includes not just check-in and bag tagging, but aircraft boarding too.
Changi Airport, in partnership with Jetstar Asia, is testing self-service machines at T1 that allow travellers to check in and tag their own luggage.
An automated aircraft boarding trial was also launched at T2 last year, in a tie-up with Germany's Lufthansa.
Low-cost giant AirAsia, which also operates at T1, supports the move towards automation if it is cost-effective. "Ultimately, cost is critical," said its Singapore chief executive officer Logan Velaitham. "It is by keeping our costs low that we are able to offer our customers low fares."
Apart from the departure floor, T1's arrival hall and baggage areas will also be expanded to boost total capacity.
The last major upgrading at T1 was completed about two years ago and cost $500 million. After four years of work, it emerged with new carpets, lights and more open spaces.