Spokesperson Tukuroirangi Morgan said a case had been filed in the High Court.
"They have got a Prime Minister who is actually keen to learn Te Reo."
The Ngāi Te Rangi Settlements Trust is concerned about the reduction of te reo Māori use by public servants.
The Finance Minister hasn't yet revealed how much the change would cost taxpayers.
"We need to see our language reflected in the society we live in."
The Newshub presenter has been learning te reo Māori in rūmaki (immersion) classes since last year.
It's Te Wiki o Te Reo Māori, the perfect time to practice - karawhiua!
The band admitted it changed one thing on 'So True'.
Tikitiki o Putea is grounded in te ao Māori values and has already been a great success in one kura kaupapa.
