Airport boss Stephen Byron said the $18 million development would take 18 weeks to build and be ready for the first direct international flights by Singapore Airlines, starting on September 21.

The lounge and arrivals areas, designed by the new terminal's original architects Guida Moseley Brown, will create about 120 jobs during construction. The airport has closed a tender process for a duty free provider and is working with the Australian Border Force for customs and immigration requirements.

Planning for the lounge began a day after the deal for flights between Singapore and Wellington, New Zealand, and Mr Byron said the new areas would fit seamlessly with the award-winning terminal building.

Canberra firm Construction Control will fit out the 2750 square metre lounge and the 2400 square metre arrival hall.

"We'd always allowed the space for international facilities," Mr Bryon said.

"The departures area is upstairs on the third floor next to the Virgin lounge and the arrivals area is next to Virgin arrivals with a dedicated separate facility. They've been left as empty shells, awaiting an international carrier to begin service."

The lounge will be similar to a private airline club lounge, Mr Byron said. The airport was open to future private lounges being added to the terminal.

"We are actually breaking the rules here. Normally lounges like this are done by airlines for their VIP travellers, but in Canberra we are doing it and we are doing it for every international passenger flying out of Canberra."

Guida Moseley Brown partner Paul Mutton said the airport terminal and new lounges would be a fitting gateway for the national capital to the world.

"The existing terminal, which we designed, was made very light, airy and open. The international zones will continue that theme, with lots of volume in the ceilings, lot of natural light, very clear and easy and navigation through them," he said.

"Technology is a big focus on the new fit-out. The passport control facilities will be state-of-the-art and for the arrivals there will be new technology that hasn't been used in other airports in Australia so far. That's developing as well."

Laptop and smartphone charging points will be available around the lounge area and arrivals electronic smart gates will be installed.

In a code-sharing deal with Virgin Australia, flights from Singapore will arrive in Canberra on Mondays, Wednesdays, Fridays and Sundays at 8.35am, starting in September. Tickets are already on sale for the services.

Passengers travelling on to Wellington will depart from Canberra at 9.50am.

In the other direction, flights from Wellington will arrive at Canberra Airport on the same days at 10.05pm and depart for Singapore at 11.30pm.

Passengers will fly on one of nine retro-fitted Boeing 777-200s.

From Changi Airport, Singapore offers connections throughout Asia and Europe on about 90 daily flights.

Wellington Mayor Celia Wade-Brown was set to visit Canberra on Thursday to discuss future economic and cultural opportunities between the soon-to-be connected cities.

"My ultimate aim is a formal city relationship with Canberra, one that delivers real benefits for Wellington," Mayor Wade-Brown said.

"The recent deal [...] is an example of what can be achieved together."

ACT Chief Minister Andrew Barr said both governments were focused on improving productivity, livability and economic competitiveness.

"This week's delegation is an opportunity to promote the high quality services and goods that the Canberra region has to offer Wellington and New Zealand more broadly and the opportunities that Wellington companies can explore in Canberra," Mr Barr said.

- With Clare Sibthorpe