Late on Sunday, a vandal snapped off several bayonets from the wooden soldier silhouettes outside Radius Fulton Care Centre in Hillside Rd, part of the rest-home's World War 1 Armistice Day memorial.
Activities director Beth Sizemore said she was warned before the display was constructed that it could be vandalised, but she did not believe Dunedin was "that type of town''.
"I'm really, really sad that I was proved wrong.''
Staff and residents were upset the memorial, constructed with help from carpentry students and teachers at Otago Polytechnic, had been desecrated, she said.
"It is such a lot of hard work, and the guys from the polytech ... gave up their time and did that for us free, because they said it's a great community thing for them to do.''
"It's just stupid, I don't understand it.''
Although the display was well lit, there were no CCTV cameras outside the facility, and management did not plan on making a complaint to police.
Resident Lin Marshall, who helped put up the wooden soldiers, said he could not believe anyone would stoop so low as to vandalise a war memorial.
"It's a bloody needless thing ... why do it?''
