Singapore's Changi Airport Terminal 1 is undergoing a S$500 million makeover to transform it into a "Tropical City".

Some of its new features will include a massive potted orchid display rising over two storeys high, a centralised departure immigration area and a remodelled public viewing gallery.

A new departure kerbside canopy spanning the entire length of Terminal 1's facade and extending over the first two lanes nearest the pavement will shelter passengers arriving at the airport.

The Civil Aviation Authority of Singapore (CAAS) and Takenaka Corporation have signed the contract for the upgrading works, which are due to be completed by the third quarter of 2011.

CAAS said in a statement that the makeover will also improve passenger flow and enhance passenger experience.