Māori Party president Che Wilson told RNZ that a mistake had been made and it lay with party volunteers who had been "learning the ropes".
As soon as the party had found out about the error, it had made contact with the Electoral Commission.
The National Urban Māori Authority is a registered charity which runs health and social services and is part-funded by a Whanau Ora commissioning agency.
But Whanau Ora Minister Peeni Henare said he was confident no taxpayer money had been involved.
Investigations relating to donations to two political parties, the National Party and the New Zealand First Party, have resulted in charges being laid against individuals but the cases have not yet been heard in court.