Melbourne Airport plans to run international flights from its domestic Qantas and Virgin Australia terminals within five years.
The move will allow both airlines to easily switch aircraft such as the Airbus A330 and Boeing 787 between domestic and international routes.
The airport aims to install versatile 'swing gates' at the T1 and T3 terminals, which will allow international passengers to board their flights at the domestic terminal.
Three swing gates are expected to be added over the next five years with as many as five more by the late 2020s.
"What these projects are intended to do is meet that international growth challenge by using latent or spare capacity in the domestic terminals," said Melbourne Airport Planning Executive Michael Jarvis.
"It will require some surgery to the buildings but by augmenting the existing domestic piers with segregated corridors and vertical transport at the gate lounges, we can add the infrastructure to existing gates rather than building new ones," Jarvis told industry publication The Airport Professional.
Jarvis stressed that while the airport still intends "to build dedicated international gates", swing gates are a cost-effective way to boost capacity while streamlining the transfer process for many passengers.