Just over a month after Opposition Leader Tony Abbott was lambasted for suggesting incentives to develop Northern Australia, the CAPITheticAL competition was won on Thursday by Perth firm Ecoscape Australia with a design that calls for a national focus on the growth and innovation of that very region.

The total prize pool was $100,000, with $70,000 going to the winner.

The competition invited student and professional architects, landscape designers, engineers and urban planners from around the world to revisit Canberra's history and imagine how an Australian national capital might be created today, more than 100 years after the actual event.

It attracted more than 1200 registrations, with 114 entries from 24 countries.

The winning entry - The Northern Capital - proposed a parallel national capital that supplemented rather than supplanted Canberra, which would retain Parliament. The second capital would also be built on the edge of a manufactured lake, Lake Argyle, in Western Australia.

The vision was for a new eco-city in northern Australia that would be ''an inviting portal'' to take advantage of its proximity to Asia, creating new departments focused on northern and cultural development, both taking account of the indigenous contribution.

Ecoscape managing director David Kaesehagen said while the plan was hypothetical, Ecoscape had genuine ambitions to develop northern Australia. While he was not sure which was the best way, incentives to attract more people to the region should be a serious consideration. He believed building a city on Lake Argyle was ''absolutely feasible''.

''There are only 500,000 people living in northern Australia; twice as many Australians live overseas,'' he said.

''Here we have this spectacular bit of country which could do so much for Australia and are we going to ignore it and let it develop in an ad hoc way? Or are we really going to engage with it and do it in a way that symbolises what Australia is all about, particularly with its northern neighbours? The other thing central, too, is engaging with Aboriginal custodians and how we can use their culture to build a new city.''

Jury chairwoman Professor Barbara Norman, professor of urban and regional planning at the University of Canberra, said the standard of entries was excellent.

''I liked the diversity of the ideas, the imaginative interpretation and the range of colour and light,'' she said.

''And I liked the fact they really tried to look at the contemporary challenges of today compared to 100 years ago.''

The second prize of $30,000 went to Brisbane designers Brit Andresen and Mara Francis for their proposal that shows a Canberra battered by natural disasters due to climate change and reduced to just 5000 residents start to revive using age-old ideas of sustainability and land use.

The student prize went to Kate Dickinson, 26, and Annabel Koeck, 25, who completed their entry while master of architecture students at the University of Sydney.

Their project presented Canberra as a hotbed of research and innovation, including wind farms near Mount Ainslie.

Another finalist was Philip Etchells, a 27-year-old trainee architect from England, who proposed a roving Parliament that routinely set up in different locations around Australia.

The CAPITheticAL exhibition is at the Gallery of Australian Design at Commonwealth Place.

The ACT government has confirmed the Centenary Rally will go ahead as planned in October, regardless of the status of the National Trust ACT, which The Canberra Times reported on Thursday was close to insolvency.

In its February pre-budget submission to the ACT, the National Trust wrote that one consequence of government not supporting them would be that they "will not be able to continue with the Centenary of Canberra Rally".

But Centenary of Canberra executive director Jeremy Lasek said the trust had finalised sponsorships since making that submission, which ensured the event could proceed, with the money safe in a separate bank account.