The proposal, made in a budget submission to the ACT government, calls for an investment of $12-15 million for the temporary structure, to sit adjacent to the existing exhibition hall.

The structure could extend exhibition space and banqueting options which are currently limited to maximums of 2000 square metres and 600 people respectively.

A two-storey option for the structure would also supplement meeting breakout rooms, of which there are currently only four, limited to a 200-person capacity each.

"The exhibition for a large conference is really what financially drives [it]. Being able to maximise how many exhibitors you can have sponsoring and supporting a conference is really critical to an organizer," centre general manager Stephen Wood said.

"We're [also] very limited in Canberra in terms of large banquet space for gala dinners and most big national conferences will have a significant gala dinner, networking component for the event.

"There's a large market there that we often miss out on because of that lack of infrastructure."

Financial analysis by IHG, which operates the convention centre, found Canberra is missing out on $25 million in direct tourism spend and 40,000 accommodation nights each year.

The findings were based on lost and denied business data from the 2017 and 2018 calendar years, which the NCCC submission said remained reliable because business had quickly returned to pre-pandemic levels.

Mr Wood pointed to a large defence conference which has begun erecting a large marquee for its event every year, at a cost of approximately $70,000, according to a letter of support for the submission written by the conference chair.

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Conferences in key industries such as defence, cyber, health, higher education, space and government services could also build the territory's influence in these spaces, Mr Wood said.

Proposals to rebuild Canberra's convention space, built in 1989, have been ongoing since 2001.

A 2018 KPMG report found four options to rebuild would all have a greater cost than benefit earned.

The options proposed at the time ranged from as high as a $680 million development down to $152 million worth of upgrades to the existing Constitution Avenue centre.

Mr Wood acknowledged a permanent upgrade had fallen down the list of the territory's infrastructure priorities, but funding for a temporary structure could bridge that need.

A temporary structure could be built in a matter of months rather than years, Mr Wood said, and it could be dissembled and resold down the track.

The concept design by Australian Temporary Structures envisions a 30-metre by 60-metre building.

The freestanding aluminium structure could be "a permanent building that can stay there for 50 years, but it can be removed within within a couple of months, as well and relocated", Australian Temporary Structures managing director Sam Whyte said.