Whanganui mayor Michael Laws says road signs spelling the city's name with an "h" will be taken down.
On Friday the New Zealand Transport Agency took down a speed sign erected on State Highway 3 that spelled the city's name as Whanganui. The sign was installed to advise of speed limit changes on the highway north of the city.
Mr Laws ordered the sign's removal, saying the law change needed for any variation of the city's name has not been gazetted by Parliament and the only official spelling is Wanganui.
The mayor says even after the rule comes into effect, signs he considers have been misspelt will be removed.
"The Government may say [the city has] got dual spellings," says Mr Laws. "Well, we're not happy with that, but we'll accept that.
"But you jolly well put that dual spelling on the names, and if you try and impose a name that we don't want on us, guess what, your signs will end up in the dump and we really don't care how much it costs you."
The Geographic Board recommended changing the spelling of the city's name after a request by some local Maori. However, in December the Government decided the official name could be either Wanganui or Whanganui.
Whanganui iwi spokesperson Ken Mair says the iwi is disappointed the Transport Agency responded to the mayor by pulling the sign down, and says it should be replaced.