The Maori Party says a momentous legislative change has been made, allowing Whanganui to be used as an alternative official name to Wanganui.
Politicians passed the Statutes Amendment Bill in Parliament on Thursday.
Maori Party co-leader Tariana Turia says the name Whanganui has a meaning and a history that is unique to the Whanganui river, the rohe, and the iwi.
She says it always was and always will be a Maori word - it's about te reo Maori and it's about identity, dialect and culture.
Ms Turia says it's been a long wait for the change - but it was worth it.
She says she hopes all Crown entities and government departments take a lead, when they are replacing signage and letterheads by using Whanganui with an 'h'.
Land Information Minister, Maurice Williamson, has formally asked government agencies to change stationery and maps to reflect the change.