Two-thirds of Aucklanders polled favour Whenuapai as a commercial airport, says a survey conducted for the promoters.
The Waitakere City Council says 57 per cent of the 316 people interviewed last month thought it should happen as soon as possible.
The council and investor Infratil plan to develop the AirForce base as a secondary regional airport to Auckland Airport at Mangere.
Waitakere mayoral taskforce chairman Bryan Mogridge said four professional surveys over the past 12 months showed solid support for the concept.
A December survey of a similar number of Auckland region residents showed 46 per cent felt the concept was a good thing, while last month's survey of a similar number showed 65 per cent for it.
But opposition to the plan may be rising. In the December poll, 13 per cent did not think it a positive development, with 41 per cent undecided.
Last month, 21 per cent were against and 15 per cent undecided.
Mr Mogridge said the rise in negative sentiment was of no concern when so many people were in favour of it.
The difference showed people were more focused on the issue now.
In January, when the North Shore City Council surveyed 850 residents, 49 per cent were for the airport, 27 per cent against and 24 per cent undecided.
The promoters' March poll of 1200 North Shore, Rodney and Waitakere residents showed 59 per cent for, 14 per cent against and 26 per cent undecided.
Mr Mogridge said the commercial airport concept had been given extensive scrutiny and enjoyed the support of most of the region's local bodies.
He said the recent local body elections had also returned many candidates who supported a second airport.
Whenuapai Airport Action Group spokeswoman Ann Forrester said it was unfortunate that the general population had been influenced by an "expensive and expansive Infratil publicity machine".
She said the promoters were using advertisements as well as polls to try to influence the Government while the Economic Development Ministry was looking closely at future uses for the air base.
Economic Development Minister Jim Anderton said a final report was expected to come before a Cabinet committee about the middle of next month.
The Air Force has five years to move to Ohakea Air Base.
