The MP for Mangere says it is ridiculous that he will not allowed to be sworn into Parliament in Samoan.
Su'a William Sio, from the Labour Party, has been told by Parliamentary Services he cannot be sworn into Parliament on Monday in Samoan because of time constraints.
Mr Sio was sworn in as a list MP in April in Samoan and English. He won the Mangere electorate in November's election.
Mr Sio says he does not accept the reasoning that it will take too long for him to be sworn-in in his native language, especially since a precedent was set with him earlier this year.
However, he has now opted to be sworn-in in Maori.
The clerk of the House of Representatives says the rule to be sworn into Parliament in either English or Maori is done in fairness to accommodate all MPs.
Mary Harris says the Oaths and Declarations Act provides for members to be sworn in either in English or Maori, recognising the two official languages.
Ms Harris says there are 122 MPs being sworn in, and in the interest of being fair to all members and getting through the ceremony in a timely manner some restraints are needed.