Airline travelers frequently passing through Australia's Darwin International Airport may expect to experience improved changes starting as the airport starts in May its planned $75 million expansion upgrade.

Apart from increased passenger intake, other improvements include three new aircraft parking bays, nearly 11,000 square metres of extra floor space, a new Virgin Australia club lounge as well as a larger Qantas lounge.

The expansion upgrade will also result to additional departure gate lounge areas and security screening zones, new office and retail areas, and improved baggage systems.

"We're very excited to be embarking on such a major development to our airport, the biggest in our history" Ian Kew, Darwin International Airport CEO, said.

"The expansion will increase capacity dramatically, enabling us to improve efficiencies for our airline customers and terminal operators, and improve the travelling experience for our passengers."

Travellers will also get to experience new shops and food and beverage outlets, such as the Bumbu eatery by Darwin-based chef and restauranter Jimmy Shu, and the Dôme café which will have floor to ceiling airside views.

Constructed and opened in 1991, the Darwin International Airport Terminal Building was under the control of the Federal Airports Corporation. Since then, it has only received minor expansion and capacity increases.

"We are investing what will be between $70 million and $75 million in this project," Mr Kew said.

Darwin Airport, since 2007, has seen growth to spike at an average of 8.5 per cent in passenger traffic annually.