The Chinese funded project to modernise Faleolo airport is expected to have cost $US54 million.
The arrival and departure terminals were increased in size from 5500 square metres to 12,000 and designed to cater for up to 600,000 passengers a year.
Other phases of the project will include the introduction of aero bridges and dedicated power centres.
Tuilaepa said the upgrade befitted that of a modern international airport and would mean more business space from which tourism-related services could be provided, improving the experience for travellers.
