In three months' time there would be room for up to 100 seats, instead of the current 50, self check-in kiosks, an improved baggage claim area and potential for a laptop charging station and children's play area.
The expansion of the terminal, to about double its current size, followed the completion of a new apron and taxiway, new toilets and the addition of about 20 carparks.
"We used to get a lot of overflow and cars parking on the grass," Mr Chubb said.
A new fence around the carpark had not deterred thieves who targeted parked vehicles, and there were plans to install more lighting and CCTV after the upgrade was complete.
District councillor Brian McLachlan said the terminal would remain open and travellers would experience minimal disruption during the works.
"The initial stages will be mostly external. There will be some hoardings inside and along the aircraft access tunnel for safety reasons. This will reduce floor area and some seats will have to be removed," he said.
Cr McLachlan said the final result would be an "open, light and airy" space which would welcome people to Whangarei.
WDC is investigating potential sites for, and the plausibility of, a completely new airport.
The airport runway is too short for many planes in the Air New Zealand fleet.