Kiritahi Firmin is asking people to stop tagging Education House, which is at number 249 in Whanganui's Victoria Ave.
Graffiti have been appearing from time to time on the front, back and sides of the large building. Whanganui police have been informed and said they would do patrols.
The building has been landbanked against future Treaty of Waitangi land claims, and Mrs Firmin - who works at Education House, where she runs the Kimiora Trust - said it was now managed by Tupoho on behalf of Whanganui iwi.
None of the graffiti were overly offensive, but it was expensive to paint them out. She assumed the perpetrators were teenagers, and she wanted to ask them inside to see what went on in the building, where her trust provides ante-natal classes and other programmes for women.
"Let's bring our kids in so that they can understand this is a kaupapa that helps their families," she said. She has had a sign made to spread that message.