The Maori Language Commission says that providing resources for people to learn te reo Maori is proving a challenge when government funding is eroded.
Te Taura Whiri i Te Reo Maori was founded in 1987, and commission chairperson, Erima Henare, says it received about $760,000 a year at the time.
That was the equivalent of more than $10 million in today's dollars, Mr Henare told Parliament's Maori Affairs Select Committee on Wednesday.
But the current budget is only half that, $5 million, and two thirds of this goes to communities to develop their proficiency in the language.
Mr Henare says the budget's baseline had been kept the same for the past five years, but over the past 25 years its funding had gone backwards.
The public sector's appetite for its staff to learn te reo Maori has reduced, but communities were increasingly keen to learn.