Air New Zealand's business was severely affected by the pandemic. Photo / Jason Oxenham
The Commerce Commission has revealed the companies most complained about in the year to June 2020.
A document from the Commerce Commission shows Air New Zealand at the top of the pile, with 329 complaints.
The pandemic had a severe impact on Air New Zealand's business, with more than 300,000 flights cancelled by July last year.
Air New Zealand offered credits to those who had their flights cancelled, but many customers wanted their money back.
The task of rebooking flights was so arduous that Air New Zealand launched a new tool to allow customers to rebook through the website without having to go through the call centre.
Customers who booked international flights had the flexibility to book tickets on domestic routes.
The demand for flight changes led Air New Zealand chief executive Greg Foran to issue an apology to customers for the company's handling of flight-change requests.
He said as many as 75,000 people called in a single day to request changes.
"We weren't ready to handle this," he said at the time, adding that the sheer scale of the number of people wanting refunds through the call centre "really caught us in a difficult situation".
But Air New Zealand wasn't the only company to provoke the ire of the Kiwi public last year.
Larger companies tend to generate more complaints due to their scale - which is why the full list includes many of the biggest names in New Zealand business.
The nation's telcos also attracted a significant number of complaints, with Spark coming in at second place with 284 complaints and Vodafone attracting 266 complaints.
Grocery giant Foodstuffs was fourth with 157 complaints, Noel Leeming fifth with 156 complaints and Woolworth sixth at 119 complaints.
Rounding out the top 10 was Flight Centre with 118 complaints, The Warehouse with 103, 2degrees with 84 and Jetstar with 65.
The airline sold its last slots at Heathrow in 2020.