New details on a proposed international airport for Tarras are expected soon, its backers say.

In July 2020, it was revealed Christchurch International Airport had been buying up hundreds of hectares of farmland in Tarras, about 25 minutes drive from Cromwell, in Central Otago, with plans to build an international airport.

Critics of the project say there has not been enough information so far and they have yet to see anything that convinces them a new airport stacks up.

But since mid-2020 there has been little further detail.

Christchurch International Airport project director Michael Singleton said it would release information about where exactly it wanted the runway to go in the coming weeks.

"Our research phase at the moment is in full swing. We've got a number of experts doing a number of things, from counting birds through to industry experts completing detailed analysis. So that will help us select a preferred runway alignment and that's progressing really, really well, and we hope to be able to release something on that shortly."

The preferred runway alignment was meant to be out by the end of last year.

But Singleton admitted there had been delays.

"Absolutely. This is a piece of work we would have liked to have had out some time ago," he said.

"The reality is the pace of aviation coming back online has meant for the experts involved in that there's been some reprioritising. So absolutely we would have liked to have it out earlier, but that's not always the way things work out."

Duncan Kenderdine, from opposition group Sustainable Tarras, was critical of the lack of detail provided by Christchurch Airport to date.

There was no business case and communication with the community had been lacking, he said.

"[It's] a 1000 days since they've come to see the Sustainable Tarras people and the community as a whole," Kenderdine said.

"They cherry-pick who they choose to talk to. None of that seems to fit the mandate that they've been given both by their council and by ministers - which is to communicate with the community.

Sustainable Tarras chair Dr Marilyn Duxson said despite the lack of information for locals, Christchurch Airport had been busy behind the scenes on more than just researching and planning its proposal.

"They are also working very hard to curry favour with politicians, Treasury, government departments," she said.

"And they are very actively denigrating a lot of the local population who are trying to gather solid information about how the community feels."

Singleton rejected accusations opponents were being denigrated.

He admitted Christchurch Airport had not arranged specific meetings with Sustainable Tarras or carried out a town hall meeting since August 2020.

But he claimed it was actively and regularly consulting with locals in other ways.

Duxson and Kenderdine said they had seen nothing to suggest the new airport was needed, let alone the concerns the project raised about noise, greenhouse gas emissions and too many tourists.

Sustainable Tarras' household survey showed 84 percent of Tarras was opposed to the plan, while 68 percent of the wider Upper Clutha catchment was also against the proposal.

But not everyone in the settlement objected.

Tarras farmer Peter Jolly said it was just what the community needed.

"As long as it's done properly and there's no half measures, there's a lot of reasons for building an airport because I think it would be a good thing for this district.

"It would give the young people of the district opportunities that they haven't now got. They have to leave the district because there's no work for them and it would be good to be able to have more people in Tarras. We need more people."

Main image (RNZ/Nate McKinnon): Critics of the project to build an international airport in the Central Otago town of Tarras say there has not been enough information so far and they have yet to see anything that convinces them the plan stacks up.