The local Maori MP for Whanganui, Adrian Rurawhe, says the district council's decision to include the "H" in its name shows it has matured and is demonstrating leadership.
At a meeting on Friday, the council voted 10-4 to request that the New Zealand Geographic Board change the spelling of the district to include the 'H'.
The council had voted on a similar motion earlier in the month, but it was lost 7-6.
Tai Hauauru MP Adrian Rurawhe believes the decision was influenced by local iwi withdrawing themselves from representative roles on the council and other local bodies.
He said a Tupoho kaumatua, John Maihi, resigned from his role as the council's cultural advisor and 20 other iwi representatives quit their positions on different boards and trusts.
Mr Rurawhe said the decision also signalled that a lot of businesses, including the council, had accepted the spelling correction, which was important to the identity of Whanganui iwi and the wider community.