The terminal, which cost $US25 million to build, was officially opened last month but both PNG Air and Air Niugini continue to use the old terminal next door.
PNG media reported that the airlines said the rent being charged to use the new terminal, more than $60,000 a month, was too expensive for them.
Civil Aviation Minister Alfred Manase had little sympathy, however, telling parliament he had ordered both airlines to move to the new terminal by the end of the month.
The Post Courier reported Manase saying the cost was the airlines' burden to bear and that if they had a problem they should take it up with the National Airports Corporation.
