But North Shore councillor George Wood said yesterday that the process should not be rushed because of the "sacrosanct" nature of the Domain, and called for full public consultation.
"This land deal should not be done by way of a Dutch auction," he said.
Mr Wood, who is a member of the committee set up to decide whether the council should allow the designation to be extended, said a management plan for the Domain stipulated there should be no more permanent leases which would alienate more of its land.
But Auckland Council transport chairman Mike Lee said the existing railway line was already on Domain land and work was needed to stabilise an eroding bank which was in danger of collapsing on to the tracks.
"It will not affect the Domain in any meaningful way," he said of the proposal, which he noted was aimed at extending the existing railway designation rather than obtaining a lease.
"It's altering the designation to recognise the fact a railway line is crossing that sliver of land."
He said the Domain was already criss-crossed with roads and he believed a campaign by Mr Wood to block the new Parnell station was "motivated by narrow parochialism - the type of petty local body politics the Super City was meant to relegate to the past."
Councillor Sandra Coney, who chairs the Domain land committee, said it was "quite out of order" for Mr Wood, as a member of that panel involved in a formal decision-making process, to make public comments about it.
She said the seven-member committee, which held its first meeting on Tuesday and will reconvene in about three weeks, had delegated authority to make a decision without notifying an application from Auckland Transport for a public hearing.
Auckland Transport projects director Nick Seymour said the organisation had reduced the amount of land it was seeking to the minimum possible area after discussions with various parties including those associated with the Domain.
It wants KiwiRail to start the track works on December 18 to make the most of a four-week closure of the railway line, which needs to be reopened in time for trains to run to the Big Day Out music festival at Mt Smart on January 20.