The National Airports Corporation head earlier invited the people of Hela and Papua New Guinea "to witness this milestone event" which took place between 10am and 2pm on August 29.
The K77 million project was executed by NAC through the Civil Aviation Development Investment Program and funded by the government in partnership with the Asian Development Bank.
The upgrade work was done by China Civil Engineering Construction.
The upgrade was done in order to meet the heavy flow of traffic coming in and out of Tari, and Hela Province generally.
Officials said the new-look airport would ensure the smooth landing and meet standards as required by the PNG Civil Aviation and International Civil Aviation rules.
Speaking at the opening, Hela Province Governor Philip Undialu said the new terminal represented the province's vision, determination and commitment to enhancing connectivity and fostering economic growth.
He thanked China Civil Engineering, the PNG government, the NAC and the ADB for their combined efforts, noting that terminal represented more than just a physical structure.
"It symbolises our aspiration to build a stronger, more prosperous future for our community. We recognise the immense potential it holds to transform our province and region," Undialu said.