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.
The runway and aprons of Faleolo airport are due to be repaved and new lights installed with funding from the World Bank.