The Māori Council has accused Air New Zealand of appropriating Māori culture for profit.
In May, the national carried applied to trade mark a logo labelled Kia Ora, the name of it's in-flight magazine, which it said was standard practice.
Māori Council executive director Matthew Tukaki said the application for the trademark of Kia Ora was an insult to Māori culture.
"Lets be really clear here this is an insult pure and simple."
Mr Tukaki said he was threatening legal action because the language was a national treasure, not something to be profited from.
"I am sick and tired of cultural appropriation and in fact all Māori are - our language is a national treasure for all of us and we need to respect it.
"It's not here for business to use it and profit from it as they see fit," he said.
Mr Tukaki also warned the chief executive of Air New Zealand, Christopher Luxon that Māori would boycott the airline if the "hoha/nonsense" continued.
But Air New Zealand said the magazine, Kia Ora, had been published since 2007. It had a brand refresh earlier in the year, after which the application to trade mark was made.
The airline said trademarking the logo was standard practice.
It said the in-flight magazine was one of the first things customers saw when they got on their flights.
"Kia ora is also well known as our greeting on our flights and is also the first thing our customers see on our IFE [in-flight entertainment]."
Air New Zealand said it was proud to promote Māori language.
"This is simply about protecting the logo. The word kia ora has been registered to be used for a range of goods and services - dating back to 1992 - both in New Zealand and overseas."