The Star Alliance lounge has been open for about a year and Air New Zealand has been running it for the airline group of 27 carriers.
"There's been great feedback - it's one of the top rating Star Alliance lounges," said Air New Zealand's general manager customer experience Carrie Hurihanganui.
The big building projects came after feedback from passengers.
"Last year we did a lot of research with customers to find out what was important about space to relax and work - as you appreciate [there were] lots of different needs," she said.
The new international lounge at Auckland would be 20 per cent bigger than the existing one, where space is tight for visitors.
It was hoped to open it about the middle of next year and was being built on the floor above the existing one in what is airport company meeting room space and its former corporate headquarters. It will offer better views of the tarmac.
"People do like the view - they like to be able to look outside at aircraft," said Hurihanganui.
The airline was about to open a new regional lounge in the domestic terminal for Koru Club members who did not want to make the trek to the main one at the other end of the building.
It was working with regional airports Napier, New Plymouth and Palmerston North about expanding and upgrading in those centres.
In Australia, work is under way on a new international lounge in Sydney where the airline had just opened a temporary one in the meantime. It was investigating locations for a new lounge at Brisbane.
Qantas, which yesterday was announced as having the best lounges in the AirlineRatings.com, is also preparing to open open a new first-class lounge at Los Angeles International Airport's Tom Bradley terminal early next month.
Its chief executive Alan Joyce said lounges were a very important part of the package for its customers.
"That's why we've invested around the world. The other interesting thing we've noticed that particularly coming out of places in Asia they want to eat before they get on the aircraft so they can sleep on those sectors."
House of Travel commercial director Brent Thomas said lounges were important to differentiate full service carriers from low-cost operators.
"From a business traveller's perspective we know that lounges are very important as a way of making sure they're refreshed. It's part of the decision-making process about what airline they'll travel on."
He said the increasing number of families with lounge access were being catered for by airlines which were making separate areas for children.