Not sure, just got this announcement...
Melbourne Airport And we're off! The first flight from our newly opened T4 took off today. There's more to come in the next few months
Melbourne Airport has opened the doors to Australia’s newest domestic terminal, located just south of Terminal 3. The staged opening of the new Terminal 4 (T4) saw Tigerair Australia commence flights on Tuesday 18 August. Jetstar and Regional Express (Rex) will join Tigerair in the new Terminal 4 in the coming months.