Public transport links are at the centre of the latest fight over Wellington Airport's $1 billion expansion plan.

For a little over two months, the airport has engaged with the public on what they plan to do with recently-purchased land that sits beside the current facility.

The proposals will see the airport extend out into neighbouring suburbs, as part of the 2040 Master Plan - the upgrade which the airport argues is needed to accommodate a doubling in passenger numbers in 19 years' time.

The current idea is to turn the land into more roads, more space for planes, and more car parks.

During the consultation, both local residents and environmental organisations offered their opposition.

They expressed concern over what bigger and more frequent planes flying into and out of the city would do for the capital, both in terms of carbon emissions, and noise.

But in a submission entered by Greater Wellington Regional Council (GWRC) there was a worry the plans did not take into account the impact a bigger airport would have on road transport.

"The airport is a key part of traffic in the eastern suburbs and in Wellington," said regional councillor, and chair of the Climate Committee, Thomas Nash.

"As a consequence of that, it contributes to the emissions of cars, fossil fuel private cars.

"With our commitment to reduce emissions, we want to make sure if the airport does expand, then that will not result in a massive increase of emissions."

Four conditions given to the airport to prevent rising emissions

In their submission, GWRC gave four conditions to ensure a bigger airport didn't mean longer traffic jams, or a higher emissions profile.

Allow free and frequent access for Metlink public transport buses, so Metlink can provide a convenient, direct and affordable service Provide a prominent space for public transport to bring people into, and pick people up from, the departures and arrivals areas Direct a proportion of car parking fees into improving active and public transport options into the airport Impose a limit on the number of car parks at the airport

"We wanted to make sure that if this designation goes ahead," Nash said, "and the expansion goes ahead in the future, then we won't be undermining our mode shift goals: to shift from car transport to public transport and cycling and walking.

"Hopefully, the airport could take into account the suggestions we're making without it really having to come to an adversarial question.

"We're simply saying that there should be free and frequent prominent access for public transport to the airport."

Surprise at the council's submission

In a statement sent to RNZ, the Chief Executive of Wellington International Airport Limited, Steve Sanderson, said he was surprised by the submission made by GWRC on the airport's expansion plan.

"We were interested to see these comments as we have always supported and promoted bus services as an important option for our customers, and have worked with Greater Wellington on plans to re-establish an airport bus for several weeks now."

The capital currently has no public transport option for getting to or from the airport.

The Airport Flyer - which took passengers all the way from Lower Hutt to the airport - has not been running since November, when the then-operator, NZ Bus, withdrew.

At the time, the airport said they were looking to get a new and improved service going by next year, and was working with Tranzit to deliver that.

It never materialised.

No immediate replacement - new service 15 months away

In February, GWRC made the decision to incorporate the Flyer into the Metlink network, and make it a public service.

However that will take time, and GWRC has estimated it won't be running until July 2022 - a full 15 months away.

"We would like to have a new service up and running by next month, as intended before Greater Wellington made the decision to take over the service," Sanderson said.

"The best thing Greater Wellington can do for public transport access is continue working with the Airport to establish a fast, easy and affordable option for customers as quickly as possible."

That was refuted by Nash.

"It is certainly not my understanding that Greater Wellington has had anything to do with the decision by the airport and whoever was involved in the tender process to run that service for the airport not going ahead.

"That's not a decision that Greater Wellington made, that's a decision that the airport and the companies involved in that tender have made.

"All we are doing now is stepping into the breach to try to provide public transport which we were prevented doing before because of the rules."

But he added he was pleased to hear the airport supports public transport.

"I guess a test for them is for them to be able to commit to providing free access for public buses to the airport precinct without levying a charge to the transport operator, and also to provide frequent access."