Both spellings of the city's name need to be made official by the Geographic Board, which is responsible for New Zealand place names. This cannot be done until the required legislation is passed through Parliament, which now looks set to be a drawn-out process.
The current legislation allows for dual names, meaning both names or spellings of a name must be used, such as Aoraki-Mt Cook, but not for alternative names.
This minor detail was due to be changed under the Statutes Amendment Bill, a catch-all bill passed each year which allows small changes to different pieces of legislation to be made in one go.
However, unlike most decisions made in Parliament, the Statutes Amendment Bill must be approved by all MPs rather than being decided in a majority vote.
The Green Party MPs were the only ones to vote against the allowing of alternative names for Wanganui. This means a completely separate bill will need to be drawn up and go through the select committee process.
Whanganui MP Chester Borrows said the situation was frustrating.
"The Greens really aren't being helpful," he said.
Because the decision to gazette both spellings of the city's name was government policy, he could not introduce a private member's bill to Parliament.
"The only way this could happen quickly is if the bill was passed under urgency, and I don't see that happening," Mr Borrows said.
He would not want to speculate on how long it would take to draw up a bill and have it become legislation.
Wanganui Mayor Annette Main said she would like to see the minister's decision formalised sooner rather than later.
However, Green Party MP Catherine Delahunty told the Wanganui Chronicle yesterday that her party had voted against the current Statue Amendment Bill because the spelling of Wanganui was an issue that needed to be debated.
Ms Delahunty said Statute Amendment Bills were intended to be non-controversial. "No one in their right mind could say that the H issue is non-controversial.
"So the Greens believe that this is an issue that should be debated properly in Parliament" she said.
The party believed the city should have the correct Maori spelling. "The bill as it currently stands doesn't recognise the status of local iwi clearly enough," she said.
Timeline
September 2005: Wanganui District Council agrees to put the H debate into the 2006 referendum.
February 2006: Referendum'06 returns a result of 3026 (18 per cent of people who voted) votes for the H and 13,670 (82 per cent of people) votes against the H.
May 2008: Te Runanga o Tupoho announce they intend to make an application to the New Zealand Geographic Board to change the name Wanganui to Whanganui.
February 2009: Tupoho's application is made to the Geographic Board.
February 2009: Wanganui District councillors put the H to the vote. Seven councillors vote to keep Wanganui, five vote to change to Whanganui.
March 2009: The Geographic Board approves Tupoho's application.
May 2009: Public consultation on the H debate opens. More than 900 submissions are received.
September 2009: The Geographic Board makes its decision on the city's name, in favour of the Whanganui spelling. Then-mayor Michael Laws denounces it as "racist and wrong", and says he had a "constitutional responsibility to fight this decision until there is no fight left in my body". The decision is forwarded to Minister for Land Information Maurice Williamson, who is to make the final decision.
May 2009: Public consultation by the Geographic Board on the H debate opens. The H debate is to be put to referendum. Of those who voted, 22 per cent were in favour of the H and 78 per cent voted against it.
December 2009: Maurice Williamson comes to Wanganui to announce his decision: Both Wanganui and Whanganui will be formally gazetted.
March 2010: Horizons Regional Council votes to adopt the Whanganui spelling. NZTA puts up its first Whanganui roading sign, which is later taken down after protests from Mr Laws.
2012: Wanganui and Whanganui are yet to be formally gazetted as official names.