The grateful settlers commissioned a monument in white marble of a weeping woman, representing grief. It was formally unveiled in December 1865.
Its inscription reads: "To the memory of those brave men who fell at Moutoa 14 May 1864 in defence of law and order against fanaticism and barbarism."
That wording annoyed famous American writer Mark Twain when he visited Whanganui in 1895.
In his 1897 book about his travels in Australia and New Zealand he said those upriver men who fell were patriots, fighting for their homes and country, and they were not fanatics.
The controversial wording is "archaic", says Whanganui mayor Hamish McDouall who is pleased an interpretation panel is to be erected near the monument, explaining that the wording is "of its time".
Wording for that panel is now being approved by Whanganui iwi.
Mr McDouall was pleased the memorial was being preserved - "It's really good that the ministry have come along to do this. We've been working through the other monuments and they are spruced up and looking great."
The Queen's Chain at Pākaitore/Moutoa Gardens has yet to be given attention.