There, conservationist Jim Lynch decided to create the world's first fully fenced eco-sanctuary that would transform a single valley from the "biological desert" of the early 1990s to its pre-human state.

The Zealandia concept aimed to reintroduce bird species and reptiles that had all but disappeared from the New Zealand mainland.

It relied on a corporatism - paying tourists, cafes, and other facilities - for funding, a move not without criticism from some parts of the conservation movement.

But the results speak for themselves.

It is now a paradise for native wildlife, reintroducing 18 species into the 225-hectare valley, six of which had been lost from the mainland for over 100 years.

It draws in roughly 120,000 visitors a year, is worth tens of millions of the local economy, and has become a significant drawcard, particularly for visiting cruise ships in Wellington.

On Friday, a delegation from the ACT visited Zealandia, signing an agreement that will see local conservationists partner with the organisation to learn from their experience.

The delegation included representatives from the ACT's highly successful Woodlands and Wetlands Trust, which, among other things, has helped reintroduce bettongs and quolls at Mulligans Flat Sanctuary.

Trust general manager Jason Cummings said his project was the "toddler" to the "teenager" Zealandia.

Mr Cummings said the valley was a model for Mulligans Flat to work towards.

"Zealandia is about 15 to 20 years ahead in its development as a sanctuary, both its conservation programs, its facilities, its eco-tourism programs," Mr Cummings said.

"With our memorandum of understanding and the engagement our staff have had previously, we're very much looking to advance our development by learning from what's happened here over the past 20 years."

The Trust wants to build a visitor and learning centre, for researchers, rangers and tourists, and wants to position the sanctuary as an eco-tourism destination. Already it is planning to install advertising in Canberra Airport to coincide with the start of international flights in September.

Mr Lynch said his vision for the valley had mostly been realised now. The wildlife was nearly at its population limits, the organisation was a strong part of the city and economy, and Zealandia was now turning its sights to improving biodiversity beyond the sanctuary's fence.

He said partnership with the ACT Woodlands and Wetlands Trust would be highly valuable.

"I would bet everything I've got that they've got more than enough capability to do the job," he said.