The timing of when people can have their say on Wellington's massive airport expansion is being eyed suspiciously by locals.

An artist impression of Wellington Airport upgrade. Photo: Supplied

A proposed $1 billion upgrade was unveiled by the airport in October last year.

It was the blueprint for how it would accommodate a forecasted doubling in passenger numbers by 2040.

Since then, Wellington International Airport Limited (WIAL) has purchased a golf course and Miramar South School land, which would allow the development to go ahead.

But the upgrade was then put on hold in June, as a result of the decimation of international travellers due to Covid-19.

That hasn't stopped the WIAL looking to get the consent to complete those developments when the project recommences.

On 10 December, two Notices of Requirements were issued by the Wellington City Council, outlining the new plans.

Submissions run over the summer period and end on 12 February.

But one residents' group has called foul.

No Fly Zone founding member Benoit Pette said: "The timing is not an accident".

"It's unfair because doing so basically shuts [out] the community.

"And the fact they choose this time to the consultation period that is at the lowest time of the year, in terms of what the engagement could be, is really telling."

The airport said it submitted its plans last December and February.

'Nothing deliberate or sinister' about timing: Council

The actual decision over when to issue the Notice of Requirements and open them to public engagement was made by the council.

In a statement, the council - which owns one third of the airport - said it would have held it sooner but had to go back to the airport for further information.

"This took longer than we would have liked, but there is nothing deliberate or sinister about notifying it at this time as asserted," a council spokesperson said.

Additionally, people have been given more time than usual to have their say, than for a normal Notice of Requirement.

"To ensure submitters have adequate time to consider and submit on the Notices of Requirement, the council has extended the legal submission period (required under the Resource Management Act) from 20 working days to 30 working days," a statement from WIAL said.

"This extension was agreed in consultation with Wellington Airport."

Pette wanted an extra month on top of that so people can make a submission once Christmas commitments were fulfilled.

Concerns over the sustainability remain

Pette is preparing a public awareness drive, if the council says no.

The airport's expansion includes a brand new terminal, freight facilities, and additional aircraft parking spaces - all to accommodate a forecasted doubling of passenger numbers.

The expansion plans had previously provoked the ire of other residents, and environmental group, Guardians of the Bays, wants the plans to be "reined in".

Pette said: "If we are indeed in a climate crisis, and we need to reduce emissions, we shouldn't allow them to grow.

"While aviation is providing a great service to the community, and it should be allowed to grow in the future, it should only do so if it's sustainable.

"Until it's sustainable, it shouldn't grow."