The airport said it was in advanced negotiations with the golf club to buy the land.
International flights, which currently park at the northern end of the terminal, will "flip" to the southern end, with regional and domestic flights parking to the south.
For several years Wellington Airport has seen a number of construction projects, including a series of terminal expansions, a large parking building and an on-site hotel.
But Wellington Airport chief executive Steve Sanderson said an overhaul was now needed, with existing international facilities struggling to cope with peak periods. It was important the airport did not "get behind" dealing with passenger growth in the way that Auckland Airport has.
During the upgrade there would were "unavoidable" changes to the way passengers were transported to flights, including around a third of flights requiring passengers being bussed to and from the terminal.
"To date ... we've managed to maintain a reasonable level of service and I think one of the big takeaways [of earlier projects] is that when people can see you're doing stuff to improve things, they are a lot more tolerant, unlike at Auckland Airport, where people can't see improvements, and that's when they don't forgive you," Sanderson said.
"The last thing we want is to get behind, and we already feel that our international terminal where we're running out of gates now and our level of service there is getting to a marginal level."
The master plan was based on "normal, business as usual" passenger growth of around 2-3 per cent each year, the rate at which Wellington Airport had been expanding for two decades.
The developments outlined in the plan are estimated to cost around $1 billion, a price which excludes the airport's plan to extend the runway by more than 350m into Lyall Bay to allow some wide-bodied jets to take off on long haul flights.
The extension plan has been put on hold after a successful legal challenge by the New Zealand Air Line Pilots' Association, which argued that the application should revisit Wellington Airport's relatively short runway end safety area.
At a presentation on Tuesday morning, Sanderson said the airport anticipated resubmitting its safety proposal to the CAA before Christmas.
Regional screening 'when, not if'
Sanderson said expansion was designed around centralised screening of all passenger when they arrive at the airport.
Although Wellington Airport has only one terminal, international passengers are screened separately from most domestic flights, while most regional flights undergo no security screening.
This was going to change in time, Sanderson said.
"It's not if, it's when we will see regionals and domestic and international [passengers] all pretty well screened at the same level," Sanderson said.
"It's always been on the agenda in New Zealand because we've always been an outlier when it comes to regional aircraft that are not screened."
'Vote of confidence'
Wellington Chamber of Commerce chief executive John Milford said the master plan was a vote of confidence in the region.
"It's essential the airport gets ahead of the expected doubling of travellers by 2040, and this will do that, and it will help future-proof the vital links our economy needs with our important markets," Milford said.
"This plan underlines the urgency of building proper road and public transport links between the airport and the city and region otherwise the expected economic benefits will be squandered."
