An Air New Zealand Koru Club member says she felt like a ''second-class citizen'' after being rejected at the airline's Auckland International Airport premium lounge.

The woman, who was travelling with a teenage child, was told at the door she couldn't get in and that she had to go to the airport's own Strata Lounge.

Air New Zealand - experiencing heavy demand for its Koru Lounge - is now notifying passengers in advance if they should go to the Strata Lounge, used by other airlines and open to all passengers for a fee.

The airport company has been providing overflow space at peak travel periods and said today it was "working together with Air New Zealand on different short and long-term lounge solutions at the international terminal".

The woman traveller said she was "dumped" out of the lounge without being asked but did receive a letter of explanation and apology after complaining.

But she said "no apology can make up for the dictatorial nature of that," and she said she would investigate whether her membership terms had been breached.

An airline service and support staff member wrote and told her Koru staff had wanted to advise in advance alternative arrangements, to avoid disappointment on the day and had arranged Strata access in advance for her next trip.

Yesterday the airline said it was now notifying those who would miss out on the Koru Lounge rather than miss out on a seat there which a spokeswoman said was a better outcome.

Some other travellers who had recently been in Koru Lounges were disappointed.

One said he had been a Koru member since its inception "many moons ago" but last month decided not to renew his subscription for a variety of reasons.

"More often than not the lounges are full to overflowing and it's hard to find seats let alone have any peace and quiet. Quite frankly they sometimes resemble a packed food hall in a suburban shopping centre," he said.

Another said the lounges were always packed and noisy and the food and beverage selection inferior to Strata.

"As a very regular flyer and a once loyal Air NZ supporter I have all but stopped travelling Air NZ," he said.

Another said the airline didn't treat Koru members equally.

"I fly out of Rotorua, domestically, pretty much every week. I pay the same membership as, say, someone doing the main trunks regularly (but) the regional lounges have inferior food and beverages to the main lounges," he said.

On a per kilometre travelled basis, he calculated he paid more on regional flights than on a main trunk route.

"Then when it comes to Rotorua we don't even have a lounge," he said.

Air New Zealand is rebuilding its Auckland Airport regional lounge to triple its capacity.

It is part of a $60 million investment in lounges throughout New Zealand over the next two years.

The new Auckland regional lounge will cater for up to 265 customers and is scheduled to open in the middle of next year.

There are also plans for the airline's Wellington Airport domestic lounge to undergo a refurbishment in the coming months, with seating to increase by 10 per cent to 374.

A new regional lounge is currently under construction at Tauranga Airport and will offer three times more seating than the current lounge. It is expected to open later this year. Plans are also underway for brand-new regional lounges in Christchurch and Nelson.

Air New Zealand general manager customer experience Anita Hawthorne said last month the airline is focused on continued investment in its network of lounges to enhance the customer experience.

"Air New Zealand's customers are at the core of our business and we expect to see annual passenger numbers grow from 17 million to 19 million over the next two years, so it's important to invest in our lounges in order to meet this growth."